As the father of twelve, I can tell you that I sometimes know what my children need before they ask. However, what I as an earthly father only sometimes know, our eternal Father always knows. Which inevitably leads to the question: If God knows what we need before we even ask, why bother asking at all?
First, it is crucial to recognize that supplication should not be seen as the sole sum and substance of prayers. Far from merely being a means of presenting our daily requests to God, prayer is a means of pursuing a dynamic relationship with him.
Furthermore, God ordains not only the ends but the means. Thus, to ask, “Why pray if God already knows what we need?” is akin to asking, “Why get dressed in the morning and go to work?” For that matter if God is going to do what he is going to do anyway, why bother doing anything? God has ordained that the work we do and the prayers we utter both produce results. The fact that God knows the future does not imply that our futures are fatalistically determined any more than our knowledge that the sun will rise causes the sun to rise.
Finally, while our heavenly Father knows what we need before we even ask, our supplications are in and of themselves an acknowledgement of our dependence on him. And that alone is reason enough to pray without ceasing.
For further study, see Hank Hanegraaff, The Prayer of Jesus: Secrets to Real Intimacy with God (Nashville:W Publishing Group, 2001).
“And when you pray, do not keep on babbling like pagans, for they think they will be heard because of their many words. Do not be like them, for your Father knows what you need before you ask him.”