Bible Verses About Shewbread: Not lawful for any but the priests to eat, except in extreme cases

The cohen answered David, "I don't have any regular bread; however, there is consecrated bread - but only if the guards have abstained from women.

David answered the cohen, "Of course women have been kept away from us, as on previous campaigns. Whenever I go out on campaign, the men's gear is clean, even if it's an ordinary trip. How much more, then, today, when they will be putting something consecrated in their packs!"

So the cohen gave him consecrated bread, because there was no bread there other than the showbread that had been removed from before ADONAI to be replaced by freshly baked bread on the day the old bread was removed.

He entered the House of God and ate the Bread of the Presence!" -- which was prohibited, both to him and to his companions; it is permitted only to the cohanim.