There have been several occasions in my life when I have been asked this question. Out of curiosity, I did a short search to see how others have answered this question, and here are some of the answers that have been offered:
1. To come to know God and build a relationship with Him
2. To ask for strength, healing, or to make requests or petitions
3. To come to understand God’s will for us
4. Because we are commanded to do so
In addition to these reasons, I wish to offer my own thoughts on why we need to pray.
First, when we call ourselves Christians this means that we are taking upon us the name of Christ and trying to be like Him. When Christ was on the earth He set an example for us by praying. He prayed for guidance, He prayed for his disciples and followers, He prayed in gratitude and praise, He prayed when he instituted the sacrament, when He was in the Garden of Gethsemane, and when He was on the Cross. So, if we are calling ourselves Christian, and becoming like Christ, then we should pray, as He did. (Mark 1:35, Luke 5:16, John 17:11, John 17:20-21, Luke 10:21, Mark 14:22, Matthew 26:39, Luke 22:44, Matthew 27:46).
Prayer is indeed our opportunity to come to know God and build a relationship with Him. However, I think it is critical to understand that in order to build that relationship we must understand that prayer requires two-way communication. Building a relationship with God is similar to building relationships with people around us, conversations need to go both ways; we talk, and then we listen. It is the same with God. Prayer allows us the opportunity to tell God how we are feeling, ask for guidance, assistance and answers to questions, but it also is our opportunity to learn from Him what His will is for us. HOW we discern His will for us will be another blog post.
Another reason for prayer is for the purpose of repentance. Christ atoned for our sins so that we can be worthy and pure when we enter into God’s presence. Only He can grant us forgiveness for the sins that we have committed. Prayer is a means for confessing our sins. The Lord has promised us that “I, the Lord, forgive sins, and am merciful unto those who confess their sins with humble hearts” (D&C 61:2).
We can also pray and ask God to help us find purpose in our lives. He has a plan for us and desires to lead and guide us. I know from experience that when I have humbled myself in prayer and offered myself as a tool for Him to use, God has guided me and directed me in making life plans and decisions. He has even given me purpose that gets me through performing the mundane and seemingly purposeless tasks of daily life.
Finally, I think one of the most important purposes of prayer is to bring our will into correspondence with God’s will. I think that many people pray and then become upset when their prayers are not answered. Even though God loves us, it is not always His will nor is it possible for Him to give us the things that we desire. I have a friend who prayed for a unicorn every day for quite a while when she was a child, but not surprisingly, she never got one. Was this because she lacked faith? I don’t really think so. If you aren’t receiving answers to your prayers, or your prayers aren’t answered in the way that you want them to be answered, maybe you need to evaluate what you are praying for and instead ask God what you should be praying for.
A Latter-Day Saint/Mormon bible dictionary notes that the purpose of prayer is “to secure for ourselves and for others blessings that God is already willing to grant, but that are made conditional on our asking for them. Blessings require some work or effort on our part before we can obtain them. Prayer is a form of work, and is an appointed means of obtaining the highest of all blessings.”
When praying, I think it is important to first, rely on the spirit to know what to pray for, and then to believe that He will answer our prayers, through faith (Isaiah 55:8-9).
Why do you think we need to pray?
(for more about prayer, I highly recommend this speech: http://lds.org/general-conference/2007/04/using-the-supernal-gift-of-prayer?lang=eng)