This is from Ray Pritchard from a blog titled: “If God Is Sovereign, Why Pray?”

Reason 1: God invites us to ask for what we need (Matthew 7:7-8; Psalm 81:10).

Reason 2: We don’t know what we really need (Romans 8:26).

Reason 3: God knows what we need before we ask Him (Matthew 6:8).

Reason 4: We don’t pray to inform God about anything (Psalm 147:4).

Reason 5: We pray to express our total dependence upon our Heavenly Father.

Reason 6: We pray because God is honored by our persistent faith (Luke 18:1-8).

Reason 7: We pray because He’s God and we’re not.

Reason 8: We’re to give God no rest (Isaiah 62:6-7).