Hebrews 6 continues the call from chapter 5 to move beyond milk. The first principles are good: repentance, faith toward God, baptisms, laying on of hands, resurrection of the dead, and eternal judgment. But a foundation is for building on. Verses 4 to 8 then give one of the most serious warnings in the New Testament. It describes people who were enlightened and tasted the heavenly gift and then fell away. Like land that drinks rain but bears only thorns, such a life does not produce what God intended. The letter does not explain exactly who these people are, and these sheets do not guess.
Verse 9 changes the tone completely. But, beloved, we are persuaded of better things for you, and things that accompany salvation. The evidence is their love. They served the saints and kept serving them, and God is not unrighteous, so as to forget this. The letter wants them to keep going with the same diligence, not sluggish, but imitators of those who through faith and perseverance inherited the promises.
Abraham shows how. God swore by himself, since he could swear by no one greater, and Abraham, having patiently endured, obtained the promise. People use oaths to end disputes. God added an oath to his promise so that by two immutable things, in which it is impossible for God to lie, his people would have strong encouragement. This hope is an anchor of the soul, sure and steadfast. It enters within the veil, where Jesus went as a forerunner and became a high priest forever after the order of Melchizedek.