4. see his face--revealed in divine glory, in Christ Jesus. They shall see and know Him with intuitive knowledge of Him, even as they are known by Him (1Co 13:9-12), and face to face. Compare 1Ti 6:16, with Joh 14:9. God the Father can only be seen in Christ.
      in--Greek, "on their foreheads." Not only shall they personally and in secret (Re 3:17) know their sonship, but they shall be known as sons of God to all the citizens of the new Jerusalem, so that the free flow of mutual love among the members of Christ's family will not be checked by suspicion as here.

JFB.