An animal horn represents the animal's strength, so horn is a metonym for strength. God speaks of making Israel strong as if Israel were an animal, and he were to cause its horn to grow. AT: "I will make the people of Israel strong" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])
The word "house" is a metonym for the family that lives in the house. Here it refers to the people of Israel, the descendants of Jacob whom God called Israel. AT: "the people of Israel" or "the nation of Israel" (See: [[rc://en/ta/man/translate/figs-metonymy]])