Sunday. The Sabbath. The Lord’s Day. A delight to my soul.
13 “If you turn back your foot from the Sabbath, from doing your pleasure on my holy day, and call the Sabbath a delight and the holy day of the Lord honorable; if you honor it, not going your own ways,or seeking your own pleasure, or talking idly; 14 then you shall take delight in the Lord, and I will make you ride on the heights of the earth; I will feed you with the heritage of Jacob your father, for the mouth of the Lord has spoken.” — Isaiah 58:13-14 esv
pdb

Manton points out: A thing may be hidden two ways, either to conceal it, or else to cherish and keep it. And it is kept in the heart, not the brain, or mind, and memory only, but the heart, the seat of emotions. To hide the word in our hearts, is to understand and remember it, and to be affected to it and with it.