Revelation 5:10: “You have made them to be a kingdom and priests to serve our God, and they will reign on the earth.”
New Testament has a complete different structure of priesthood and understanding of the kingdom of God. In the Old Testament only one tribe of Israel could be priests. In the New Covenant every believer is a rightful priest. In the Old Covenant only Israel was considered to be the rightful nation (kingdom) of God. In the New Covenant your belonging or not belonging to the kingdom of God does not depend on your nationality, but on you being or not being born again. Everyone who has been born again is a priest unto God and is part of the kingdom of God.