Jesus teaches us that when we approach God in prayer, address him as "Father." Compared to what other religions teach, calling the creator of the world a term that is so personal is unusual - this is an amazing gift. This is how Jesus prays (eg: John 17:1, 5, 11, 21, 24, 25). The only time Jesus didn't address God this way was when he was quoting scripture on the cross.
Jesus uses the term "father," because that is who created everything. We do not pray to some random force that made the universe - we pray to someone who is listening, caring and knows who we are. He is only a prayer away - he is immediately accessible; we are never alone. Since he is the sovereign, powerful God, we do not need to be afraid (of God, of death, of losing salvation, to ask for help).
Matthew 7:9-11 God is a giving father who has our best interests in heart. This may also mean disciplining us for our own good. God wants to have an intimate relationship with us, he wants us to learn to speak like we are his children. We are a part of a family with other believers (he is "our father), and should pray for one another. The Lord's prayer should bring us closer to God and closer to each other.
How do we become a child of God? John 14:6 shows that Jesus' sacrifice,our acceptance of this, and a relationship with Jesus will allow us to call God our father. For those who may have had a relationship but have fallen out of touch; remember the prodigal son - God is still there watching and waiting with love.
