The first time believers are referred to is in Acts 9:2 (NKJV), “and asked letters from him to the synagogues of Damascus, so that if he found any who were of the Way, whether men or women, he might bring them bound to Jerusalem.” Here believers were ?of the Way.
Acts 5:14 (NKJV), “And believers were increasingly added to the Lord, multitudes of both men and women.” Believers includes the consecrated followers of Jesus and the household of faith. (Galatians 6:10)
Acts 11:26 (NKJV), “And when he had found him, he brought him to Antioch. So it was that for a whole year they assembled with the church and taught a great many people. And the disciples were first called Christians in Antioch.”
Romans 15:14 (NKJV), “Now I myself am confident concerning you, my brethren, that you also are full of goodness, filled with all knowledge, able also to admonish one another.” 1 Corinthians 15:1 (NKJV), “Moreover, brethren, I declare to you the gospel which I preached to you, which also you received and in which you stand.” Please note that “brethren” can refer to brethren in Christ, Jewish brethren, or natural brothers. The quoted scriptures are two examples where believers are called brethren.
1 Corinthians 1:2 (NKJV), “To the church of God which is at Corinth, to those who are sanctified in Christ Jesus, called to be saints, with all who in every place call on the name of Jesus Christ our Lord, both theirs and ours.” “Saints” means holy ones. So the name saints may be applied to holy men of old, not only to consecrated believers in Christ.
1 Corinthians 12:27 (NKJV), “Now you are the body of Christ, and members individually.”
Revelation 14:4 (NKJV), “These are the ones who were not defiled with women, for they are virgins ?(2 Corinthians 11:12. virgins are not involved with the world, but waiting for their bridegroom, Jesus?). These are the ones who follow the Lamb wherever He goes. These were redeemed from among men, being firstfruits to God and to the Lamb.”
Revelation 17:14 (NIV), “They will wage war against the Lamb, but the Lamb will triumph over them because he is Lord of lords and King of kings–and with him will be his called, chosen and faithful followers.”
Revelation 21:9 (NKJV), “Then one of the seven angels who had the seven bowls filled with the seven last plagues came to me and talked with me, saying, “Come, I will show you the bride, the Lamb’s wife.”