Salvation by grace through faith alone

If the Father does the choosing and through the power of the Holy Spirit, the changing, then He does the preserving. Because the Father initiates it all, I am assured of my salvation because the Holy Spirit sealed me and set me apart “Holy” for the use of and by the will of the Father. He will preserve me. I have nothing to boast about, for I’m only in gratitude for the mercy I received that I don’t deserve (grace).

However, if I do any of the choosing, changing or accepting, where does God’s sovereignty fall in the process? If I initiate or complete the process, shouldn’t I share the responsibility to maintain my salvation? Can I do that? Do I have enough faith today? Can I ever be good enough? Am I ever Holy enough? How about tomorrow? Last week? My salvation is always in doubt because the bible tells me “NO!” to all those questions. The scripture say’s:

6 For all of us have become like one who is unclean, And all our righteous deeds are like a filthy garment; And all of us wither like a leaf, And our iniquities, like the wind, take us away.
Isaiah 64:6 (NASB)

8 and those who are in the flesh cannot please God.
Romans 8:8 (NASB77)

How can we reconcile those verses with the idea that there is anything we do (like choosing/accepting) that will please God while we are still in the flesh? Aren’t we saying that not only can we do something good in God’s eyes; we are saying it pleases God so much that he grants us access to His thrown.  With that, there becomes a real opportunity for me to boast. After all, I leave the impression to an un-believing world, that not only could not Christ save me without my help, I’ve done what they could also, but weren’t perceptive enough to do on their own as well.