The moment we think that our act of praying or not praying contributes to God's being for us, it is self-righteousness.
Piper explains in this video excerpt.
“Christ died for my sins” is shorthand for “The only way to have God 100% on my side is to receive and rest in—as a gift—who Christ is and what he has done for me, and not who I am and what I did for him.” That's the heart of the gospel . . .