God has given us prayer as a wartime walkie-talkie so that we can call headquarters for everything we need as the kingdom of Christ advances in the world. Prayer gives us the significance of front-line forces, and gives God the glory of a limitless Provider. The one who gives the power gets the glory. Thus prayer safeguards the supremacy of God in missions while linking us with endless grace for every need.
John Piper (2010). “Let the Nations Be Glad!: The Supremacy of God in Missions”, p.65, Baker Academic