The first doctrine mentioned in Hebrews 6:1-2 is the doctrine of repentance. It is only fitting that it is the first mentioned, because this is the primary condition to the New Birth, and the first requirement of the Christian Faith, and entering into a covenant relationship with the true and living God. The Greek Word for repentance is:

3341  metanoia-
a change of mind (heart), as it appears to one who repents of a purpose he has formed or of something he has done

For a person to enter into the Kingdom of God, He or she must first have a change of mind about the way their life is going, and to have a change of mind as to whom they choose to serve. In Hebrews 6, we see that the operative phrase we must deal with is repentance from dead works.
This is what Jesus began to teach right from the beginning of His ministry:

John 6:27
27     Labour not for the meat which perisheth, but for that meat which endureth unto everlasting life, which the Son of man shall give unto you: for him hath God the Father sealed.

Again, we see a related theme in Matthew 6:

Matt 6:19-24
19     Lay not up for yourselves treasures upon earth, where moth and rust doth corrupt, and where thieves break through and steal:
20     But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal:
21     For where your treasure is, there will your heart be also.
22     The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.
23     But if thine eye be evil, thy whole body shall be full of darkness. If therefore the light that is in thee be darkness, how great is that darkness!
24     No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.

Matt 4:17
17     From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.

The word translated "repent" here is basically the same word, and is only as different as the word repentance is different from repent.

3340  metanoeo-
1) to change one's mind (heart), that is, to repent
2) to change one's mind (heart) for the better, to amend heartily with abhorrence of one's past sins

Mark 1:14-15
14     Now after that John was put in prison, Jesus came into Galilee, preaching the gospel of the kingdom of God,
15     And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel.

Jesus was saying in essence, "change your mind concerning  your life style, and believe the good news about the Kingdom of God  that I am declaring".
Jesus commissioned His disciples to go and preach the gospel. We see that an integral part of this gospel was that men should repent, or change their minds about the course they were on.

Mark 6:12
12     And they went out, and preached that men should repent.

Jesus mentioned the repentance of Nineveh as a perfect illustration of God's grace falling on a people after they repented. And then in the following verses, he demonstrates what true repentance is:

Luke 11:32-36
32     The men of Nineve shall rise up in the judgment with this generation, and shall condemn it: for they repented at the preaching of Jonas; and, behold, a greater than Jonas is here.
33     No man, when he hath lighted a candle, putteth it in a secret place, neither under a bushel, but on a candlestick, that they which come in may see the light.
34     The light of the body is the eye: therefore when thine eye is single, thy whole body also is full of light; but when thine eye is evil, thy body also is full of darkness.
35     Take heed therefore that the light which is in thee be not darkness.
36     If thy whole body therefore be full of light, having no part dark, the whole shall be full of light, as when the bright shining of a candle doth give thee light.

When a person changes his mind as to the course of life he or she is following, and they choose to follow the True and Living God, Jesus taught that it will be evident to all who knew them.   

When we come to God in a True repentance, we have decided to set our affections on Him and the things of Him, rather than on the things of the world.

The true Christian walk is one of turning our backs on the lure of the world, and turning our hearts and affections toward God. As Joshua told the Israelites, they needed to decide whom they were going to serve. God is a jealous God, and He seeks those who will give Him their all. Repentance is a matter of choice. Repentance is truly changing our minds concerning our lives and our lifestyles.

I Jn 2:15-17
15     Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him.
16     For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world.
17     And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.

Rom 12:1-2
1     I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.
2     And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.

Col 3:1-7
1     If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God.
2     Set your affection on things above, not on things on the earth.
3     For ye are dead, and your life is hid with Christ in God.
4     When Christ, who is our life, shall appear, then shall ye also appear with him in glory.
5     Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry:
6     For which things' sake the wrath of God cometh on the children of disobedience:
7     In the which ye also walked some time, when ye lived in them.

Jesus taught that repentance is absolutely essential for a person to be saved. But he also taught of God's longsuffering toward us.

Luke 13:1-9
1     There were present at that season some that told him of the Galilaeans, whose blood Pilate had mingled with their sacrifices.
2     And Jesus answering said unto them, Suppose ye that these Galilaeans were sinners above all the Galilaeans, because they suffered such things?
3     I tell you, Nay: but, except ye repent, ye shall all likewise perish.
4     Or those eighteen, upon whom the tower in Siloam fell, and slew them, think ye that they were sinners above all men that dwelt in Jerusalem?
5     I tell you, Nay: but, except ye repent, ye shall all likewise perish.
6     He spake also this parable; A certain man had a fig tree planted in his vineyard; and he came and sought fruit thereon, and found none.
7     Then said he unto the dresser of his vineyard, Behold, these three years I come seeking fruit on this fig tree, and find none: cut it down; why cumbereth it the ground?
8     And he answering said unto him, Lord, let it alone this year also, till I shall dig about it, and dung it:
9     And if it bear fruit, well: and if not, then after that thou shalt cut it down.

Though the Lord does bear long with us, and gives us Grace, it is obvious that He expects us to bear fruit. True repentance will bear fruit. The light of Christ will shine brightly in a Christian.

Acts 26:19-20
19     Whereupon, O king Agrippa, I was not disobedient unto the heavenly vision:
20     But shewed first unto them of Damascus, and at Jerusalem, and throughout all the coasts of Judaea, and then to the Gentiles, that they should repent and turn to God, and do works meet for repentance.

Acts 17:30-31
30     And the times of this ignorance God winked at; but now commandeth all men every where to repent:
31     Because he hath appointed a day, in the which he will judge the world in righteousness by that man whom he hath ordained; whereof he hath given assurance unto all men, in that he hath raised him from the dead.

No one is excluded from God's plan of salvation. He is a righteous Judge, and no respecter of persons. The desire of God is that all men should come to repentance.

2 Pet 3:9
9     The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance.

Luke 5:31-32
31     And Jesus answering said unto them, They that are whole need not a physician; but they that are sick.
32     I came not to call the righteous, but sinners to repentance.

Luke 15:1-32
1     Then drew near unto him all the publicans and sinners for to hear him.
2     And the Pharisees and scribes murmured, saying, This man receiveth sinners, and eateth with them.
3     And he spake this parable unto them, saying,
4     What man of you, having an hundred sheep, if he lose one of them, doth not leave the ninety and nine in the wilderness, and go after that which is lost, until he find it?
5     And when he hath found it, he layeth it on his shoulders, rejoicing.
6     And when he cometh home, he calleth together his friends and neighbours, saying unto them, Rejoice with me; for I have found my sheep which was lost.
7     I say unto you, that likewise joy shall be in heaven over one sinner that repenteth, more than over ninety and nine just persons, which need no repentance.
8     Either what woman having ten pieces of silver, if she lose one piece, doth not light a candle, and sweep the house, and seek diligently till she find it?
9     And when she hath found it, she calleth her friends and her neighbours together, saying, Rejoice with me; for I have found the piece which I had lost.
10     Likewise, I say unto you, there is joy in the presence of the angels of God over one sinner that repenteth.
11     And he said, A certain man had two sons:
12     And the younger of them said to his father, Father, give me the portion of goods that falleth to me. And he divided unto them his living.
13     And not many days after the younger son gathered all together, and took his journey into a far country, and there wasted his substance with riotous living.
14     And when he had spent all, there arose a mighty famine in that land; and he began to be in want.
15     And he went and joined himself to a citizen of that country; and he sent him into his fields to feed swine.
16     And he would fain have filled his belly with the husks that the swine did eat: and no man gave unto him.
17     And when he came to himself, he said, How many hired servants of my father's have bread enough and to spare, and I perish with hunger!
18     I will arise and go to my father, and will say unto him, Father, I have sinned against heaven, and before thee,
19     And am no more worthy to be called thy son: make me as one of thy hired servants.
20     And he arose, and came to his father. But when he was yet a great way off, his father saw him, and had compassion, and ran, and fell on his neck, and kissed him.
21     And the son said unto him, Father, I have sinned against heaven, and in thy sight, and am no more worthy to be called thy son.
22     But the father said to his servants, Bring forth the best robe, and put it on him; and put a ring on his hand, and shoes on his feet:
23     And bring hither the fatted calf, and kill it; and let us eat, and be merry:
24     For this my son was dead, and is alive again; he was lost, and is found. And they began to be merry.
25     Now his elder son was in the field: and as he came and drew nigh to the house, he heard musick and dancing.
26     And he called one of the servants, and asked what these things meant.
27     And he said unto him, Thy brother is come; and thy father hath killed the fatted calf, because he hath received him safe and sound.
28     And he was angry, and would not go in: therefore came his father out, and intreated him.
29     And he answering said to his father, Lo, these many years do I serve thee, neither transgressed I at any time thy commandment: and yet thou never gavest me a kid, that I might make merry with my friends:
30     But as soon as this thy son was come, which hath devoured thy living with harlots, thou hast killed for him the fatted calf.
31     And he said unto him, Son, thou art ever with me, and all that I have is thine.
32     It was meet that we should make merry, and be glad: for this thy brother was dead, and is alive again; and was lost, and is found.

See in this parable how the young man changed his mind about the course of life he was following. We are told in verse 17, that "he came to himself". He realized that the road he was on led to a dead endůso he changed his mind, and got on the right course.

Matt 21:28-31
28     But what think ye? A certain man had two sons; and he came to the first, and said, Son, go work to day in my vineyard.
29     He answered and said, I will not: but afterward he repented, and went.
30     And he came to the second, and said likewise. And he answered and said, I go, sir: and went not.
31     Whether of them twain did the will of his father? They say unto him, The first. Jesus saith unto them, Verily I say unto you, That the publicans and the harlots go into the kingdom of God before you.

Repentance and freedom from the bondage of sin go hand in hand.

Luke 24:45-47
45     Then opened he their understanding, that they might understand the scriptures,
46     And said unto them, Thus it is written, and thus it behoved Christ to suffer, and to rise from the dead the third day:
47     And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.

859  aphesis-
1) release from bondage or imprisonment
2) forgiveness or pardon, of sins (letting them go as if they had never been committed), remission (forgiveness) of the penalty

When we truly repent and turn to God, sin has no more hold on us:

Rom 6:14
14     For sin shall not have dominion over you: for ye are not under the law, but under grace.

The Holy Spirit Gives us the power to obey God once we repent:

Acts 2:38
38     Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.

Acts 10:43
43     To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins.

Rom 3:25
25     Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;

Matt 26:28
28     For this is my blood of the new testament, which is shed for many for the remission of sins. (KJV)

Acts 13:38-39
38     Be it known unto you therefore, men and brethren, that through this man is preached unto you the forgiveness of sins:
39     And by him all that believe are justified from all things, from which ye could not be justified by the law of Moses.

Eph 1:7
7     In whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace;

Col 1:14
14     In whom we have redemption through his blood, even the forgiveness of sins:


We have seen that the doctrine of repentance encompasses these things:

Repentance is necessary for salvation.

By it's very definition, repentance is changing one's mind as to the course of life he or she has been pursuing, and making a conscious decision to follow the Ways of the Lord, and acting on that decision.

One cannot merely decide to live for Jesus; there must also be a viable proof as to the effect that decision has had in one's life. Just calling oneself a Christian does not make a person a Christian. In yielding to Christ, one becomes occupied with the things of God more than he or she is with the things of this world. People will just naturally be able to see this difference.

This is bearing fruit fit for repentance.

4) When one repents, sin has no more dominion over him.