Exodus 19:6

A kingdom of priests] a kingdom of which every member is consecrated to the service of God, and so 'a holy nation': see on Leviticus 20:24, The designation expresses also the high calling of Israel. They are to be the medium of communicating the knowledge of the divine nature and will to the world. In general, it may be allowed that the Jewish nation has fulfilled its destiny. It has taught the world true religion. Through its rejection of the Messiah its sacred function has passed over to the Christian church, to which St. Peter transfers the titles given to Israel in these two vv.: see 1 Peter 2:9; Revelation 1:6.