He is like an eternal, unfailing fountain. The more it pours forth and overflows, the more it continues to give. God desires nothing more seriously from us than that we ask Him for much and great things. In fact, He is angry if we do not ask and pray confidently (Hebrews 4:16)
From the Large Catechism, Second Petition, "Concordia - The Lutheran Confessions," Concordia Publishing House