The "Our Father" is the perfect prayer since Christ himself taught it to us. It is therefore so fitting we say it just before we approach the altar to receive communion. I reminds us of the awesomeness of God, the reverence for his name, the greatness of his kingdom, the submission to his will required to be part of the kingdom on earth and in heaven. The prayer then foreshadows the transubstantiation of Christ in the Eucharist by asking for our daily bread! Finally it asks for forgiveness of our sins, and the openness we must have to forgive others who also come home to the Lord. Why? We are all sinners in a fallen world where temptation lurks everywhere. We will all fall from time to time, and have a need to come back into the good graces of God.
PS Sorry my thoughts are so jumbled this week. I feel like I have a huge case of writers block!