Greg Boyd, in Across the Spectrum, writes,
“a great deal of what God does in the world is influenced by whether his people pray.”
“Scripture describes God’s character as unchanging (Mal 3:6), but it never teaches that God is unable to change in any respect (e.g., his intentions, experiences) … And it teaches that God sometimes chooses not to change his mind (Num 23:19; 1 Samuel 15:29; Ezekiel 24:14; Zechariah 8:14) but never that he cannot change his mind.”