It is the Lord (ο κυριος εστιν). John's quick insight appears again.

Girt his coat about him (τον επενδυτην διεζωσατο). First aorist middle (indirect) indicative with which note διεζωσεν εαυτον in John 13:4. Apparently Peter threw on the upper garment or linen blouse (επενδυτην) worn by fishers over his waistcloth and tucked it under his girdle.