A few days ago I had a painful medical test. During the times it hurt most I sang in my mind and heart a song I have sung for years "Jesus, remember me when you come into your kingdom". I sing this to my daughter when we snuggle for bedtime and I sang it to her when she was an infant and I rocked her asleep. Since this song/prayer has dropped into my heart it is a source of strength in all times.
One of my professors at seminary suggested each congregation had a handful of songs that would help shape their spirituality. This way the people would have a common spiritual source and if they dropped into the heart then it they would be a resource at any time and in any need.
Do you have a prayer/song of your heart?