6 So the priest gave him holy bread; for there was no bread there but the show bread that was taken from before Yahweh, to put hot bread in the day when it was taken away.
1 Samuel 21:6 Cross References - WEB
Leviticus 24:5-9
5 “You shall take fine flour, and bake twelve cakes of it: two tenths of an ephah shall be in one cake.
6 You shall set them in two rows, six on a row, on the pure gold table before Yahweh.
7 You shall put pure frankincense on each row, that it may be to the bread for a memorial, even an offering made by fire to Yahweh.
8 Every Sabbath day he shall set it in order before Yahweh continually. It is an everlasting covenant on the behalf of the children of Israel.
9 It shall be for Aaron and his sons. They shall eat it in a holy place; for it is most holy to him of the offerings of Yahweh made by fire by a perpetual statute.”
Matthew 12:3-4
Mark 2:25-27
25 He said to them, “Did you never read what David did, when he had need, and was hungry—he, and those who were with him?
26 How he entered into God’s house at the time of Abiathar the high priest, and ate the show bread, which is not lawful to eat except for the priests, and gave also to those who were with him?”
27 He said to them, “The Sabbath was made for man, not man for the Sabbath.