In 1 Nephi 21:3,8 and the rest of chapter 21 (Isaiah 49), the servant called "Israel" is Christ. Thus the "house of Israel" is the "house of Christ." All who accept Christ in the proper way and follow him become a part of the house of Israel (compare 1 Nephi 14:1-2; 3 Nephi 16:13). [Zarahemla Research Foundation, Study Book of Mormon, p. 47]