1 Peter 2:9–10

Peter calls a "holy nation" those who once were not a people

9But you are a chosen race, a royal priesthood, a holy nation, a people for God’s possession, so that you may proclaim the virtues of the one who called you out of darkness into his marvelous light.

10you who once were not a people, but now are the people of God; who had not received mercy, but now have received mercy.

Study it word by word

In its context

7To you then who believe is the honor; but to those who do not believe, The stone that the builders rejected, this has become the head of the corner,

8and A stone of stumbling and a rock of offense. They stumble because they disobey the word, and to this they were also destined.

…

11Beloved, I urge you as foreigners and pilgrims to abstain from the fleshly desires which wage war against the soul.

12keeping your conduct among the nations good, so that, in what they speak against you as evildoers, by observing your good works they may glorify God on the day of visitation.

Read all of 1 Peter 2

Its words in the original

HolinessPraise and worshipPurposeThe Church and Community