It is impossible for those who have once been enlightened, who have tasted the heavenly gift, who have shared in the Holy Spirit, who have tasted the goodness of the word of God and the powers of the coming age— and then have fallen away—to be restored to repentance, because they themselves are crucifying the Son of God all over again and subjecting Him to open shame.
When the Israelites saw it, they asked one another, "What is it?" For they did not know what it was. So Moses told them, "It is the bread that the LORD has given you to eat.
In their hunger You gave them bread from heaven; in their thirst You brought them water from the rock. You told them to go in and possess the land which You had sworn to give them.
Significance
Language colored by OT wilderness references. Continues exodus/wilderness motif from chapters 3-4. Those who fall away parallel wilderness rebels who experienced God's provision yet apostatized. Warning against abandoning Christian community. The wilderness pattern becomes paradigmatic by analogy—just as Israel experienced deliverance, provision, and God's presence yet rebelled, so the danger exists for new covenant believers who have been "enlightened," tasted heavenly realities, and shared in the Holy Spirit. The impossibility of renewal doesn't stem from God's unwillingness but from the apostate's condition—they "are crucifying the Son of God all over again" and hold him up to contempt.