I think Paul sums up the partnership we have with God very nicely in Colossians 1:22-23,
“But now he has reconciled you by Christ’s physical body through death to present you holy in his sight, without blemish and free from accusation – if you continue in your faith, established and firm, and do not move from the hope held out in the Gospel.”
Who does the saving? God. By grace? Yes, by grace. Regardless of anything on our behalf? No. We must continue in our faith and not move from the firm foundation that the Gospel provides if we are to enjoy the free gift of reconciliation accomplished through Christ. We often confuse Ephesians 2:8-9 to mean we have absolutely nothing to do with our faith or that nothing we do can impact or influence it. Those verses read, “For it is by grace you have been saved, through faith—and this not from yourselves, it is the gift of God— 9not by works, so that no one can boast.” But Paul is entirely consistent in saying we don’t earn our salvation but we do have something to do with it. The two can happen at the same time. They are not mutually exclusive. Grace is still grace but we must be willing participants in God’s process of reconciliation.