These articles and books speak to the heart.
Five Mantles of Prayer
Prayer grows, it develops, and it increases and decreases. Prayer takes shape and form, it is secret, silent, and significantly more powerful than words can tell for surely God would rather have a heart without words than words without a heart. This prayer guide facilitates intimacy and power with God.
Unity: the Cry of the Heart
https://www.amazon.com/Unity-Diane-Hale/dp/1494286025/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1480555983&sr=8-7