1 Peter 2:9

9 But you are A CHOSEN RACE, A royal PRIESTHOOD, A HOLY NATION, A PEOPLE FOR God’s OWN POSSESSION, so that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light;

It sounds like Peter is addressing only Jews; however, he is addressing both Jews and Gentiles who are Christians of the church. Before the church was born, these concepts indeed were for Israel. They were a chosen race; they had special priests; they were a holy nation (Israel); and God did possess them (who were obedient) as His own people.

But though the Abrahamic covenant was made in the beginning exclusively for Jews, there is a provision made in the covenant for all people who believe. In Genesis 1`2:3 and 22:18, God promised that in Abraham and in his seed all the nations of the earth who blessed Israel would be blessed. Christa through his church (made up of both Jews and Gentiles) is the promised blessing to all people. He is of the seed of Abraham and is the mediator of the New Covenant (Heb. 12:24).

We will look now at each of these four terms: A CHOSEN RACE. Indeed, the Jews were and are the chosen race. But through the blessing of the New Covenant, all believers, metaphysically speaking, enter into that race. Gentiles will never really become the same race as the Jews, but they are brought into that group of chosen ones. All believers are chosen by God to salvation.

A royal PRIESTHOOD. This was a title for all of Israel until their disobedience and rejection of the Messiah (Ex. 19:6). At the present time the church is a royal priesthood with Jesus Christ as our priest. Soon in Christ’s kingdom we will experience an ultimate fulfilment of that priesthood—ruling with Christ (Rev. 5:10; 20:6).

A HOLY NATION. Israel was called a holy nation until their unbelief. At that time God replace them with the church. I suppose Peter here is envisioning the church as a group of people without borders; a people with order and regulation, much like a nation.

A PEOPLE FOR God’s OWN POSSESSION. From the beginning, when God established the people and the Nation of Israel, His idea was that they would be His own possession. But this possession was based on the condition that they would obey Him and keep His covenant (Ex. 19:5). But those who were part of the church, who were children of God, God declared them already to be His own possession—whom He bought with the price of His own blood (1 Cor. 6:19; Titus 2:14).

After God tells us who we are (through Peter), He gives us our mission; to proclaim His excellencies. And of course, with all that we are (above), we are well qualified and prepared for our mission.