The All-Sufficient God
Ac 17:25 "Nor is He worshiped with men's hands, AS THOUGH HE NEEDED ANYTHING, since He gives to all life, breath, and all things.
The word "need" does not apply to God. God does not NEED anything. He is sufficient in Himself. God does not need us, but we need Him.
He does not need our prayers. On the other hand, we need to pray to Him. He does not need our praises. On the other hand, we need to praise Him. He does not need our service. On the other hand, we were created to serve Him.
We don't add anything to God if we do these things and we don't take anything from Him if we refuse to do it. He isn't made any greater if we pray to Him, praise Him, serve Him etc. He isn't made any lesser if we don't.
He was fine without us in eternity past, and He will be fine without us in eternity future, should He choose it to be so. In His justice, He could have sent us all, sinners, to hell and be separated from Him for all eternity. And He will still be God, the all-sufficient One.
When we do His commandments, it is not for God's benefit. It is for ours "'And the LORD commanded us to observe all these statutes, to fear the LORD our God, FOR OUR GOOD ALWAYS..." De 6:24
Since this is the case, we should never think that we are doing God a favor if we pray to Him, praise Him, serve Him etc. We don't earn brownie salvation points with God and cause Him to save us because we do these things.
No. Salvation is not a reward given by God because we scratched His back, so to speak. It's not God saying: "You scratch My back. I'll scratch yours. Give me what I need and I will give you what you need."
No. You can't truly give anything to the source of everything. Salvation proceeds from the pure love and goodness of God. And His saving love and goodness are expressed in Christ Jesus.
If you trust in Him and what He did on the cross, you will be saved. Not as a reward earned but as a kindness and mercy freely bestowed.