Heb 6:6  If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.

Hebrews 6:6  If they shall fall away,…. This is not supposed of true believers, as appears from Heb_6:9 nor is it to be supposed of them that they may fall totally and finally; they may indeed fall, not only into afflictions and temptations, but into sin; and from a lively and comfortable exercise of grace, and from a degree of steadfastness in the Gospel; but not irrecoverably: for they are held and secured by a threefold cord, which can never be broken; by God the Father, who has loved them with an everlasting love, has chosen them in Christ, secured them in the covenant of grace, keeps them by his power, has given them grace, and will give them glory; and by the Son, who has undertook for them, redeemed and purchased them, prays and makes preparations in heaven for them, they are built on him, united to him, and are his jewels, whom he will preserve; and by the Holy Ghost, whose grace is incorruptible, whose personal indwelling is for ever, who himself is the earnest and seal of the heavenly inheritance, and who having begun, will finish the good work of grace: but falling away, so as to perish, may be supposed, and is true of many professors of religion; who may fall from the profession of the Gospel they have made, and from the truth of it, and into an open denial of it; yea, into an hatred and persecution of what they once received the external knowledge of; and so shall fall short of heaven, and into condemnation: for,

to renew them again unto repentance, is a thing impossible: by “repentance” is meant, not baptism of repentance; nor admission to a solemn form of public repentance in the church; nor a legal repentance, but an evangelical one: and so to be “renewed” unto it is not to be baptized again, or to be restored anew to the church by repentance, and absolution; but must be understood either of renovation of the soul, in order to repentance; or of the reforming of the outward conversation, as an evidence of it; or of a renewing of the exercise of the grace of repentance and to be renewed “again” to repentance does not suppose that persons may have true repentance and lose it; for though truly penitent persons may lose the exercise of this grace for a time, yet the grace itself can never be lost: moreover, these apostates before described had only a show of repentance, a counterfeit one; such as Cain, Pharaoh, and Judas had; and consequently, the renewing of them again to repentance, is to that which they only seemed to have, and to make pretensions unto; now to renew them to a true repentance, which they once made a profession of, the apostle says is a thing “impossible”: the meaning of which is not only that it is difficult; or that it is rare and unusual; or that it is unsuitable and improper; but it is absolutely impossible: it is impossible to these men to renew themselves to repentance; renovation is the work of the Holy Ghost, and not of man; and repentance is God's gift, and not in man's power; and it is impossible for ministers to renew them, to restore and bring them back, by true repentance; yea, it is impossible to God himself, not through any impotence in him, but from the nature of the sin these men are guilty of; for by the high, though outward attainments they arrive unto, according to the description of them, their sin is the sin against the Holy Ghost, for which no sacrifice can be offered up, and of which there is no remission, and so no repentance; for these two go together, and for which prayer is not to be made; see Mat_12:32 and chiefly because to renew such persons to repentance, is repugnant to the determined will of God, who cannot go against his own purposes and resolutions; and so the Jews (l) speak of repentance being withheld by God from Pharaoh, and, from the people of Israel; of which they understand Exo_9:16 and say, that when the holy blessed God withholds repentance from a sinner, אינו יכול לשוב, “he cannot repent”; but must die in his wickedness which he first committed of his own will; and they further observe (m), that he that profanes the name of God has it not in his power to depend on repentance, nor can his iniquity be expiated on the day of atonement, or be removed by chastisement:

seeing they crucify to themselves the Son of God afresh; who is truly and properly God, begotten of the Father, and of the same nature with him, in whom he greatly delights; this is Christ's highest name and title; and it was for asserting himself to be the Son of God that he was crucified; and his being so puts an infinite virtue in his sufferings and death; and it heightens the sin of the Jews, and of these apostates, in crucifying him. He was once crucified, and it is both impossible and unnecessary that he should be, properly speaking, “crucified afresh”, or “again”; it is impossible, because he is risen from the dead, and will never die more; it is unnecessary, because he has finished and completed what he suffered the death of the cross for; but men may be said to crucify him again, when, by denying him to be the Son of God, they justify the crucifixion of him on that account; and when they lessen and vilify the virtue of his blood and sacrifice; and when both by errors and immoralities they cause him to be blasphemed, and evil spoken of; and when they persecute him in his members: and this may be said to be done “to themselves afresh”; not that Christ was crucified for them before, but that they now crucify him again, as much as in them lies; or “with themselves”, in their own breasts and minds, and to their own destruction. Now this being the case, it makes their renewal to repentance impossible; because, as before observed, the sin they commit is unpardonable; it is a denial of Christ, who gives repentance; and such who sin it must arrive to such hardness of heart as to admit of no repentance; and it is just with God to give up such to a final impenitence, as those, who knowingly and out of malice and envy crucified Christ, had neither pardon nor repentance; and besides, this sin of denying Christ to be the Son of God, and Saviour of men, after so much light and knowledge, precludes the way of salvation, unless Christ was to be crucified again, which is impossible; for so the Syriac version connects this clause with the word “impossible”, as well as a foregoing one, rendering it, “it is impossible to crucify the Son of God again, and to put him to shame”; and so the Arabic version. Christ was put to open shame at the time of his apprehension, prosecution, and crucifixion; and so he is by such apostates, who, was he on earth, would treat him in the same manner the Jews did; and who do traduce him as an impostor and a deceiver, and give the lie to his doctrines, and expose him by their lives, and persecute him in his saints.

(l) Maimon. Hilchot. Teshuba, c. 6. sect. 3. (m) Vid. R. David Kimchi in Isa. xxii. 14.

Reference

Gill�s exposition of the entire bible