4 For it is impossible for those who were once enlightened, and have tasted the heavenly gift, and have become 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, since they crucify again for themselves the Son of God, and put Him to an open shame. (Hebrews 6:4–6, NKJV)
Verse 6 gives the reason for the impossibility of renewal to repentance if Christians fall away. When fallen Christians continue to practice their sins, they forfeit the power to renew their faith. It is impossible to be renewed spiritually while continuing to sin. They are crucifying the Son of God by their willful transgressions, openly shaming Him by their return to and continuance in sin (Heb. 10:26-31). Indulging in sin instead of resisting it hardens hearts that were once enlightened, enlivened, and edified by God’s word and its promised hope. Therefore, we are warned not to let sin have a place in our hearts and lives (Heb. 3:12-13). Yes, Christians can fall away and be lost (2 Pet. 2:20-22; Gal. 5:4). And yes, fallen saints can be restored to Christ, but only by strictly putting away the sins that have prevented their repentant return to the Lord. Willful sin must cease for divine mercy to take its place (Lk. 15:17-24).
“Though you grind a fool in a mortar with a pestle along with crushed grain, yet his foolishness will not depart from him.” (Proverbs 27:22, NKJV)
The proverb depicts a process of separating the husk from the kernel of grain in a manner that is more intricate and careful than the usual threshing process. (The word “grind” means “to pound or beat small.”) Pulpit Commentary notes in this proverb “is expressed the idea that the most elaborate pains are wasted on the incorrigible fool…an obstinate, self-willed, unprincipled man cannot be reformed by any means; his folly has become his second nature, and is not to be eliminated by any teaching, discipline, or severity” (Proverbs, 519). Although pounding and grinding grain yields its intended results, you cannot beat foolishness out of a fool. You cannot pound the truth of God into a heart that is hardened by sin against it. Perhaps this is one of the reasons why it is said to be “impossible…to renew them again to repentance” who have tasted heaven’s sweet goodness and then fallen away from the Lord (Hebrews 6:4-6). Unless and until the obstinate heart softens toward God and toward His truth, the sinner will go on, unaffected by efforts to separate him (or her) from the foolishness of his sin. “Today, if you will hear His voice, do not harden your heart” (Hebrews 3:7-8)!
36 Now indeed, Elizabeth your relative has also conceived a son in her old age; and this is now the sixth month for her who was called barren. 37 For with God nothing will be impossible.” 38 Then Mary said, “Behold the maidservant of the Lord! Let it be to me according to your word.” And the angel departed from her. (Luke 1:36–38, NKJV)
Elizabeth, the mother of John, had not been able to bear children her whole life. Now, she was “well advanced in years” (Lk. 1:7). Furthermore, her husband Zacharias admitted to being “an old man” (Lk. 1:18). Yet, she conceived a son. Elizabeth’s pregnancy was a sign to Mary that, although she was a virgin, she would indeed bear a son by the power of God (Lk. 1:34-35). Notice carefully how Mary said the “impossible” would be accomplished. She had faith these things would occur to her “according to your word” (v. 38). Things that are “impossible” with man are accomplished according to the word of God, not contrary to it. Do not expect God to act against His word; He will not. Instead, when you rely on and obey God’s word, great things will be accomplished that defy human wisdom, will and power.