With all your lēbāb (לבב)

English speakers often distinguish between “heart knowledge” and “head knowledge,” but in biblical Hebrew, לבב refers to both the “heart” and the “mind” (and can further indicate “thinking,” “feeling,” or one’s “will”). To be called to love Yahweh with all our לבב implies not only our heartfelt devotion but also our thinking.

To live out this devotion to God, Moses tells the people to have Yahweh’s words on their לבב. While this does imply memorization, the point is that they should have these words on their mind in daily life. The English expression really is fitting. Like a tune we can’t get out of our heads, or something we can’t take off our minds, Moses instructs us to be deliberate about thinking on God’s Word—to be so occupied with the word of Yahweh that we are in a sense preoccupied with it, so much so that it spills out in our words and actions.—Brian L. Webster, in Devotions on the Hebrew Bible, 35