I found a great quotation of Paul Miller in a recent publication from Life Action Ministries on the connection between prayer and the gospel:
"In the gospel, the Father takes us as we are because of Jesus and gives us his gift of salvation. In prayer, the Father receives us as we are because of Jesus and gives us his gift of help. We look at the inadequacy of our praying and give up, thinking something is wrong with us. God looks at the adequacy of his Son and delights in our sloppy, meandering prayers."
Great hope for meandering, sloppy, and struggling believers who wrestle not only to pray but to pray well.