That is a question many people ask as they try to sort out what prayer is and how prayer works and does prayer actually do anything for anyone. Is God really concerned with what goes on in our lives or is God just the "watch-maker God" as some have said in the past, creating the product and then standing by to see what happens as it works? That question has been pondered through the centuries and, as is true with many faith issues, it seems to be a matter of faith. Do you believe in a God who cares about humans and desires to act on behalf of humans or do you not believe at all or believe that God is but God does not really care?
That is part of why the Gospel lection for this next Sunday is so important. It contains the prayer that many of us say weekly in worship, the prayer we call "The Lord's Prayer". It also contains a short teaching story, perhaps you can even call it a parable, and a teaching passage about the nature and character of God.
Jesus was involved in his own prayer time when his disciples asked him to "...teach us to pray, as John taught his disciples." (Luke 11:1) What follows through verse 4 is what we call The Lord's Prayer, containing all of it except the conclusion that was added later by the Church during its history.
Each phrase of The Lord's Prayer deserves its own sermon or posting but suffice it to say that many consider it to be a complete summation of the needs of the one doing the praying and an opening of one to God's will for one's life. Praising God, asking for one's daily needs to be met, asking for forgiveness as one attempts to forgive others, and asking for God's guidance to avoid the many trials of life are petitions that touch each part of human life. Then to pray the parts that are not found in Luke's Gospel add even more meaning to the pray we say together in worship weekly. "Thy kingdom come, thy will be done, on earth as it is done in heaven" opens the one praying to the completion of God's intent in both the life of the pray-er and the world in general.
Then Jesus tells a story about a man who has settled down for the night with his household when suddenly a friend knocks on his door asking for food. The drowsy sleeper at first tries to tell the seeker to go away giving him the reason that everyone is already in bed. The friend will not be deterred though, needing some bread to offer a guest so as not to be rude. Jesus concludes that even if a person will not grant the request of a friend simply because one is a friend, the person will grant the request so as not to be bothered further.
Then, Jesus teaches his disciples to ask for what they need. God will give them what they need because God is good, as earthly parents should be, giving good gifts to children such as fish or eggs and not bad things such as scorpions or snakes. Jesus concludes that if earthly parents can give good gifts to their children, then why should humans think that God would not give good gifts to God's children. He sums up the passage with idea that God is always willing to give what is needed through the action of the Holy Spirit in the lives of humans.
So, if one believes that God exists and one believes that God is good to humans and wants them to have what is good for them, then why shouldn't humans ask God for what they need, relying on God's wisdom to grant requests according to God's will and intent? (Remember in the Lord's Prayer--"thy kingdom come, thy will be done...") Prayer is the thing we do when we want to include God in our lives after we have done all we can do and seem to be at the end of our own resources, so we pray and ask God to intervene. Perhaps Jesus is teaching that a relationship exists between humans and God much like the relationship between parent and child and that relationship includes the giving of good gifts between parent and child. The relationship should be enough reason to talk to God even as we talk with humans with whom we have a relationship.
God does not promise to give humans everything they ask for. God promises to give humans what they need for daily living. What we think we need and what we actually need to survive creates a giant chasm that often blocks our relationship with God. Even when we think what we needs is best for us or others for whom we pray, God seems to know best what we need. Trusting God to act according to our needs may be the biggest test of faith in an invisible God for it involves giving control over to another and humans rarely like doing that.