Peter (1:9) calls Christians "a chosen race, a royal priesthood, a consecrated nation, a people whom God claims as his own." In doing so, he is not creating new descriptions for the community but is creating a new way of reading the Old Testament and God's choice of Israel, for these words are a quotation from Exodus 19, where God reveals to Moses the graces which the Israelites will attain if they are faithful to the Covenant which God makes with them.

Although we cannot prove it absolutely, there is a lot of evidence to suggest that this First Letter of Peter is essentially a homily preached by a bishop at the baptism ceremonies at the Easter Vigil on Holy Saturday night. In applying these words to the new followers of Jesus, Peter is passing on God's promise to them and exhorting them to live up to the grace they have received in Baptism in the new and eternal Covenant which Jesus has established with us.