The author exhorts not to fall back from the faith, 1-10; but to be steadfast, 11, diligent, and patient to wait upon God, 12; because God is most sure in his promise, 13-20.
1 Therefore, leaving the first principles of the doctrine of Christ, let us go on to perfection, not laying again the foundation of repentance from dead works and of faith toward God, 2 Of the doctrine of baptisms, of laying on of hands, of the resurrection of the dead, and of eternal judgment. 3 And this we will do, if God permits. 4 For it is impossible for those who have been once enlightened, have tasted the heavenly gift, have been made partakers of the Holy Spirit, 5 And have tasted the good word of God and the powers of the age to come, 6 If they fall away, to renew them again to repentance, seeing they crucify to themselves the Son of God again and put him to an open shame. 7 For the ground which drinks in the rain that comes often upon it and brings forth herbs fit for them by whom it is dressed receives a blessing from God. 8 But that which bears thorns and briers is rejected and is near being cursed, whose end is to be burned.
9 But, beloved, we are persuaded of better things for you, and things that accompany salvation, though we speak in this manner. 10 For God is not unrighteous to forget your work and labor of love, which you have shown toward his name, in that you have ministered to the saints and still minister. 11 And we desire each of you to show the same diligence to the full assurance of hope to the end, 12 So that you do not become slothful, but followers of those who through faith and patience inherit the promises.
13 For when God made a promise to Abraham, since he could swear by no one greater, he swore by himself, 14 Saying, "Surely blessing I will bless you, and multiplying I will multiply you." 15 And so, after he had patiently endured, he obtained the promise. 16 For men truly swear by the greater, and an oath for confirmation is to them an end of all contradiction. 17 In this, God, more abundantly willing to show to the heirs of promise the immutability of his counsel, confirmed it by an oath, 18 So that by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us. 19 This hope we have as an anchor of the soul, both sure and steadfast, and which enters into that within the veil, 20 Where the forerunner has for us entered, even Jesus, made a high "priest forever after the order of Melchizedek."
Matthew Henry Commentary - Hebrews, Chapter 6[➚]
[v.1] - "leaving the first principles" - From the Pulpit Commentary: "A further question is whether the writer merely expresses his own intention of proceeding at once in this Epistle to the more advanced doctrine, or whether he is exhorting his readers to make spiritual progress, using the first person plural, φερώμεθα (as in Hebrews 2:1 and Hebrews 4:1, φοβήθωμεν) out of sympathetic courtesy. The correspondence of this delicate form of exhortation with that of the earlier passages, the very words φερώμεθα, 'let us be borne on,' 'press forward' (implying more than mere passing to a new line of thought), and τελειότητα (which expresses personal maturity, not advanced subject of discourse), as well as the earnest warnings that follow against falling back, seem to necessitate the second of the above views of the meaning of this verse. The writer has, indeed, in his mind his intention of proceeding at once to the perfect doctrine; for he hopes that what he thus exhorts them to do they will do, so as to be able to follow him; but exhortation, rather than his own intention, is surely what the verse expresses."
[v.13] - "he swore by himself" - Reference, Genesis 22:16.
[v.14] - Quoting Genesis 22:17 (LXX).
[v.20] - Quoting Psalm 110:4 (LXX). Reference, Genesis 14:18-20.