1 Samuel 21:5
And David answered the priest, and said unto him, Of a truth women have been kept from us about these three days, since I came out, and the vessels of the young men are holy, and the bread is in a manner common, yea, though it were sanctified this day in the vessel.
Cross-reference
Leviticus 24:9
Historical context
In Leviticus 24:9, only priests may eat the showbread — the law David is bending when he takes the holy bread.
Exodus 19:15
Parallel
In Exodus 19:15, the people abstain from women before meeting God — the same practice of sexual abstinence for holiness.
Leviticus 15:18
Historical context
In Leviticus 15:18, sexual relations cause uncleanness until evening — the law behind why David's men abstained to be holy.
Leviticus 24:5
Historical context
Leviticus 24:5 gives the law for the showbread that David's men are about to eat, explaining its holiness.