Commentators highlight that the psalmist's desire for God is not just an emotional or spiritual feeling, but a physical one. The words 'longeth' and 'fainteth' describe a craving so intense it causes physical weakness, like growing pale from desire. The phrase 'my heart and my flesh' signifies that his entire being—body and soul—cries out for communion with God, showing that a deep relationship with Him engages our whole person.