Impossible?

Here's a deep theological perspective to chew on. I welcome comments.

Heb. 6:4-8

4It is impossible for those who have once been enlightened, who have tasted the heavenly gift, who have shared in the Holy Spirit,5who have tasted the goodness of the word of God and the powers of the coming age,6if they fall away, to be brought back to repentance, because[2] to their loss they are crucifying the Son of God all over again and subjecting him to public disgrace.
7Land that drinks in the rain often falling on it and that produces a crop useful to those for whom it is farmed receives the blessing of God.8But land that produces thorns and thistles is worthless and is in danger of being cursed. In the end it will be burned.

I have read this in at least 4 different translations and every one of them says "impossible". Even though "with God, all things are possible". Guess that says a lot about free will, huh? With God, all things may be possible, but with man, there are simply some impossibilities because of man's selfishness, stubbornness, and outright rebellion. May I never subject my beautiful savior to public disgrace or another crucifixion. May my land never get hard from the outpouring of rain and only produce thistles. May I never turn away from the living water of which I have tasted. I am counting the cost and finding nothing more valuable than Christ.