Numbers 3:13

3:13 because all the firstborn are mine. When I destroyed all the firstborn in the land of Egypt, I set apart for myself all the firstborn in Israel, both man and beast. They belong to me. I am the Lord.”

Numbers 8:16-17

8:16 For they are entirely given to me from among the Israelites. I have taken them for myself instead of all who open the womb, the firstborn sons of all the Israelites. 8:17 For all the firstborn males among the Israelites are mine, both humans and animals; when I destroyed all the firstborn in the land of Egypt I set them apart for myself.

Numbers 12:6

12:6 The Lord said, “Hear now my words: If there is a prophet among you, I the Lord will make myself known to him in a vision; I will speak with him in a dream.

Numbers 18:6

18:6 I myself have chosen your brothers the Levites from among the Israelites. They are given to you as a gift from the Lord, to perform the duties of the tent of meeting.