The following thoughts about the Lord's Prayer could also apply to any written prayer found in the Bible (such as the Psalms or the prayers in Paul's letters):

We are usually at a loss regarding what to say to God on behalf of another person or, alternatively, to God himself regarding the fulfillment of his purposes in the world. The Lord's Prayer frees us from the tyranny of spiritual creativity and allows us to rest in the confidence of something certain and true. Instead of fabricating something snappy to garner God's attention, Jesus would have us lose all such originality and simply plagiarize … at the [invitation] of the Lord himself.