From Russell M. Nelson, CR April 1995:

Peter used uplifting terms in a prophecy regarding our day. He identified members of the Church as “a chosen generation, a royal priesthood, an holy nation, a peculiar people.” The adjectives chosen, royal, and holy we recognize as elevating. But what about peculiar? A modern dictionary defines peculiar as “unusual,” “eccentric,” or “strange.” What kind of compliment is that?

But the term peculiar as used in the scriptures is quite different. In the Old Testament, the Hebrew term from which peculiar was translated is segullah, which means “valued property,” or “treasure.” In the New Testament, the Greek term from which peculiar was translated is peripoiesis, which means “possession,” or “an obtaining.”

Thus, we see that the scriptural term peculiar signifies “valued treasure,” “made” or “selected by God.” For us to be identified by servants of the Lord as his peculiar people is a compliment of the highest order.

When we know who we are and what God expects of us—when his “law [is] written in [our] hearts”—we are spiritually protected. We become better people. 

Peculiar is used in only seven verses of the Bible. In the Old Testament, it is used five times (see Ex. 19:5; Deut. 14:2; Deut. 26:18; Ps. 135:4; Eccl. 2:8). In each instance, it has been translated from the Hebrew term that means “valued treasure.” In the New Testament, peculiar is used two times (see Titus 2:14; 1 Pet. 2:9). In each instance, it has been translated from a Greek term that signifies “possession,” or “those selected by God as His own people.”