We had some friends over the other evening, and the issue of petitionary prayer came up. Here was one set of questions on the table (in my paraphrase): As Christians we don't believe that Christianity is falsified if you pray for something, even something "reasonable" that seems like it would advance the kingdom of God and that is not selfish, and you don't get it. But in that case, we don't really expect to receive our petitions. So why bother to engage in petitionary prayer? What's the point? Moreover, if you are praying for spiritual strength (e.g., to resist some temptation), and you know that you will have to put in the effort yourself to resist the temptation anyway, why bother praying about it? Why not just do your best to resist the temptation?
Now, it would be simple enough to answer these questions by saying that God tells us to pray for our needs, including our spiritual needs. So do it because it's commanded, end of discussion. Scripture is unequivocal in telling us to engage in petitionary prayer: "In everything by prayer and supplication with thanksgiving, let your requests be made known unto God." (Phil. 4:6) "Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;" (Eph. 6:18) "Give us this day our daily bread...and deliver us from evil." (The Lord's Prayer) "You have not because you ask not..." (James 4:2) "If any man lack wisdom, let him ask of God" (James 1:5). "Pray for us...I beseech you to do this, that I may be restored to you the sooner." (Hebrews 13:19) "Watch and pray that you enter not into temptation" (Matt. 26:41)
I think, though, that these and other verses give us more information than just a bare commandment. The most important part of this information, mysterious as it must seem, is that in some way we cannot fully understand God has elected to use our prayers as part of the causal chain for bringing about his will in our lives and in the world.
That seems incredibly inefficient. Why should I have to pray for my daily bread? God knows what I need. He could just send it! God knew the good that Paul could do if released from prison. (Assuming that Paul was the author, or one of the authors, of Hebrews.) If it was God's will to release him from prison, why did people need to pray for it? Why should God accomplish his will in any way whatsoever by means of our prayers?
But that question could be asked of anything. God could have spelled out his message by special revelation to each individual on earth, but it pleases him (at least most of the time) by the foolishness of preaching to save them that believe. (I Cor. 1:21; cf Romans 10:14ff) God owns the cattle on a thousand hills and could provide all the cups of water necessary for every thirsty person, yet instead he promises a blessing to those who give a cup of water in his name. (Mark 9:41)
In other words, one thing that Scripture teaches again and again and again is that God likes to do things "inefficiently." God chooses, of his own free creativity, to make us mysteriously a part of the vast web of causal processes in this world by which to bring about his purposes. And sometimes we can mess up and not do our part. So with prayer. It is just as true of prayer as it is of telling others about Christ, speaking up instead of being silent, or doing your daily work: God has a job for you to do, and if you don't do it, the ball might get dropped. Something might not happen that would otherwise have happened. Oh, to be sure, as with all our sins both of commission and of omission, God can nonetheless bring good out of evil. He is never taken by surprise. But the point is that praying is a form of working for God's kingdom. It is part of what we can and should be doing. It is causal. We don't have to understand precisely how this is so to know that it is so and that this is why God tells us to pray.
Notice that this is true even of praying for our own needs. It is true of praying for a job, for example. Presumably if one is looking for a job one is working to that end. If you believe that God is glorified by your applying for jobs, that it is a worthwhile endeavor (a reasonable enough proposition!), then you can see that God is also glorified by your praying both for a job and for wisdom in the entire process of application and decision-making.
With that point made about the real causal role of prayer, I know that there is no danger that what follows will be interpreted as saying, "The only point of prayer is that it changes you." That isn't the only point of prayer. But it is one point of prayer, including petitionary prayer. There is no spiritual exercise that is the equivalent of prayer. Nothing else can be substituted for it. An important aspect of that spiritual exercise is genuinely, sincerely asking for something from God, thinking of God as a great King who loves you, who can grant your request, and asking for it with no irony or reservation, while at the same time submitting yourself to his will if he should choose not to grant it. That is hard. It is one of the hardest things for us Christians to do. (We have Jesus' own example of it in the Garden.) In doing this we speak to the Father as to a Person. (If that offends the classical theists in my audience, so be it.) We understand that prayer is not just a rote exercise to go through. It is not just a series of motions. It is a real transaction in a real world that we cannot see. We are speaking to Someone and asking Him for something. But at the same time, we are not treating the concrete thing we request as a right. We are not saying, "I deserve this." We are submitting to Him completely, realizing that we may not get what we ask, or at least not in any visible or sensible form.
I suggest that if one tries this for a few months, repeatedly, it will make a difference to one's spiritual character.
What this also means is that petitionary prayer shouldn't be separated off into a little box from adoration, thanksgiving, and confession of sins. That's presumably part of why the Apostle Paul uses the expression "prayer and supplication with thanksgiving." Psychologically, this makes sense. If you are asking for something from God in a concentrated and sincere way, recognizing that you are speaking to a real Personal Being, but at the same time recognizing how far above you God is, then petition will be constantly passing in and out of adoration and thanksgiving. As for confession, that will be there as well, because it will be extremely difficult to come to God in that humbleness and openness of mind without recognizing that one has things one must confess.
Note, too, that confessing sins is not an option. Christians are required to do it, to be repeatedly confessing, repenting, and seeking forgiveness, to be getting their hearts right with God. So we must pray for that reason if no other, and in the process of confessing sins, asking forgiveness, and thanking and praising God, it would be quite artificial to exclude more ordinary petitionary requests.
All of this may sound rather too obvious, or thin, or preachy. But it's what I've got to offer on this urgent, practical issue.
Prayer for the Christian is like water--an absolute need. In fact, it is so whether you feel that way or not. If you make a habit of prayer, setting aside time for it and doing it with all your might, opening your heart to God, I predict that you will come to feel it to be a need as well as knowing it to be. That can only be a good thing.