Often including the intellect as well as the affections and will; as conversely the "mind" often includes the feeling and will as well as the intellect. Romans 1:21, "their foolish heart was darkened." Ephesians 1:18, "the eyes of your understanding (the Vaticanus manuscript; but the Sinaiticus and Alexandrinus manuscripts 'heart') being enlightened." Thus, the Scripture implies that the heart and the head act and react on one another; and in men's unbelief it is the will that perverts the intellectual perceptions. John 7:17, "if any man be willing to (Greek) do, he shall know." "Willingness to obey" is the key to spiritual knowledge. See Jeremiah 17:9; Hosea 7:11, "Ephraim is like a silly dove without heart," i.e. "moral understanding".