I have been enjoying an excellent discussion with another brother and thought it would be a shame to not place my thoughts in a place where they can more easily be found. We have been talking about the nature of salvation and he is making the argument that, though salvation is a gift, it is not a final one until we actually make it home. In other words, we can walk away from God's gift and leave Him. Here is my response:

The troubling aspect of your argument is that salvation is not "by grace alone." You make man an agent of his own salvation when "salvation is of the Lord." Covenant theology well reconciles portions of scripture that seem to hold different ideas in tension such as Hebrews 6:4-8 where it seems that man can willingly choose to fall away after having been quickened by the Spirit and Ephesians 2:1-10 where we see that we who were dead have been raised to life by God who is "rich in mercy".

Romans 11:28-32 and Ephesians 1:13-14 show that "the gifts and the calling of God are irrevocable" and that "we were sealed with the promised Holy Spirit, who is the guarantee of our inheritance". As mere mortals, we cannot break the seal of the Holy Spirit. Only God can do that but we see again in 2 Corinthians 1:20-21 that God will not and cannot break His promise to us (which is salvation by the Spirit) and has again "put his seal on us and given us his Spirit in our hearts as a guarantee."

As 2 Timothy 1:7 states, "for God gave us a spirit not of fear but of power and love and self-control." If salvation has anything to do with us then we will die in fear, never knowing from one moment to the next if we can walk away from our salvation or have actually done so. The work and maintenance of our salvation must then be the Lord's so that we can walk in a spirit of freedom and liberty.

So how do all these scriptures reconcile with Hebrews 6? I think a proper understanding of God's visible covenant explains things well. It speaks of those in it (the visible church) "who have tasted the heavenly gift, and have shared in the Holy Spirit, and have tasted the goodness of the word of God and the powers of the age to come" and have yet walked away as being irredeemable. Yet, according to the rest of scripture, they can never be restored because they are "crucifying once again the son of God". I don't see within in the context that they were ever redeemed, but I do see that they cannot ever be part of God's true kingdom. They have committed "blasphemy of the Holy Spirit" as it were and proved, when the time came to reveal the truth of their commitments, that they were never "bought at a price" in the first place.

God does not lose that which He has invested in. If He did, the power of Christ's sacrifice would be useless as a means of both salvation and comfort. We find hope in the power of God's grace because it protects us not only from the world, but from our own very flesh. In fact, He has given us a new heart to prove that we are no longer under the power of the old self.