Hebrews 7:20-22

And he confirmed it to us with his solemn vow. For the former priests took their office without an oath, but with Jesus, God affirmed his royal-priesthood with his promise, saying, The Lord has made a solemn oath and will never change his mind, “You are a King-Priest forever!” So all of this magnifies the truth that we have a superior covenant with God than what they experienced, for Jesus himself is its guarantor!