I here refers to Jehovah, indicating that Jehovah will strengthen His people in Himself. They will then walk about in His name, i.e., in His person as the reality of His name (Matt. 28:19 and note Matt. 28:195). To be in God’s name is to be one with God in our daily walk by our living, walking, and having our being in God’s name (cf. Col. 3:17).