If They Shall Fall Away
Hebrews 6:4-6, the warning, as the early church read it
This is one of the hardest warnings in Scripture, and one of the most fought over. Hebrews describes people who were "once enlightened," "tasted the heavenly gift," "made partakers of the Holy Ghost", and then says that if they fall away it is "impossible to renew them again unto repentance." Chrysostom reads it with great care, refusing two errors at once: he will not soften the warning (these were real recipients of grace), and he will not let it slam the door on repentance (what is "impossible," he argues, is a second baptism, not a return). The Father in his own words below, with a plain restatement.
The Father's words are verbatim and attributed (Chrysostom, Homilies on Hebrews, NPNF, public domain; selected from the running prose, footnote apparatus omitted). The box marked "In plain terms" is our own restatement, never the Father's words.
Hebrews 6:4-6 · KJVFor it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost… 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.
"'Impossible.' No longer (he says) expect that which is not possible. (For he said not, It is not seemly, or, It is not expedient, or, It is not lawful, but 'impossible,' so as to cast them into despair), if ye have once been altogether enlightened… 'and have tasted of the heavenly gift,' that is, of forgiveness. 'And been made partakers of the Holy Ghost.'"
St. John ChrysostomChrysostom takes the warning at full strength, and takes seriously who is being warned. These are not pretenders: they were "enlightened," they "tasted" forgiveness, they "partook of the Holy Ghost." So this is a real warning to people who really received grace, not a description of those who were never in. That alone rules out treating every apostate as someone merely faking from the start.
Hebrews 6:6 · KJV · what is "impossible"?…to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh.
"What then, is repentance excluded? Not repentance, far from it! But the renewing again by the laver… To bring them to that former brightness however, is not possible; for there the whole was Grace. But it is [the work] of repentance, when those who have been made new, have afterwards become old through sins, to set them free from this old age, and to make them strong."
St. John Chrysostom"Baptism is a Cross… as it is not possible that Christ should be crucified a second time… He then that baptizeth a second time, crucifies Him again."
St. John ChrysostomHere is the key that keeps the verse from crushing anyone: what is "impossible," Chrysostom says, is not repentance, "far from it!", but a second baptism. Baptism is a once-for-all dying-and-rising with Christ; to start that fresh slate over would be to crucify Christ again, which cannot be. So the believer who has fallen cannot get the all-grace, clean-slate beginning a second time, but the road of repentance back to God is wide open, and it is repentance's very work to take those who have "become old through sins" and make them new and strong again.
Where this stands among the traditions
This is the great perseverance passage, and the traditions read it differently. The Reformed (Calvinist) read it as a warning whose function is real but whose "apostates" prove, by falling, that they were never truly regenerate, the truly elect cannot finally fall. The Arminian, Catholic, and Orthodox read it as Chrysostom does: real believers, real grace, real danger of falling away. The distinctive early-church balance, against a second error, is that falling does not put repentance out of reach (the rigorist Novatians, who denied any restoration after serious post-baptismal sin, were condemned by the church). So the older answer holds two things together that the modern debate tends to split: the warning is genuine and the fall is possible, and the door of repentance never closes, even though baptism's one-time fresh start is not repeatable. (See the letter on the Security of Salvation.)
Patristic text from Chrysostom's Homilies on Hebrews (NPNF, public domain), selected from the running prose with footnote apparatus omitted; nothing added or paraphrased within the quotation marks. Scripture in the King James Version; the plain-language lines are our own restatement. This passage in the Study Bible; Hebrews 6 at BibleHub.