Today's Gospel is unusual, not in that Jesus drove out the unclean spirit, but in that He did so without being asked. More often than not Jesus helped needy people in response to a petition. It is not as if Jesus had to be told what should be done. Rather He willed that His help would come as a result of faith manifested in a request.
God does not need to be informed about our needs. Such is not the purpose of the prayer of petition. Rather God has, for the most part, willed to respond to our needs in answer to prayer. To put it another way, and perhaps more accurately, God moves us to pray for what is right and good as part of His overall plan to do what is right and good for us.
All along Samuel was part of God's plan. He willed to send this extraordinary man to govern and direct His people because they needed Him. But he wanted Hannah, as a representative of all the people, to pray that a son would be granted her despite her apparent inability to bear a child. And pray Hannah did. In fact she prayed so fervently that Eli, observing her in the temple, thought she was drunk! In answer to her prayer she conceived and bore a son whom she called Samuel.
Our prayer of petition, should be fervent and persevering.
Lord, let Your plan for me unfold and may Your life increase in my life.