The writer speaks of Yahweh as if he were a shield because he protects his people as a shield would protect them from harm. AT: "the one who helps you and protects you" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here the word "House" represents the family or descendants. This phrase refers to the priests, who were descendants of Aaron. AT: "Descendants of Aaron" or "Priests" (See: [[rc://en/ta/man/translate/figs-metonymy]])