Therefore that disciple whom Jesus loved - John, John 13:23.
It is the Lord - He was convinced, perhaps, by the apparent miracle, and by looking more attentively on the person of one who had been the means of such unexpected and remarkable success.
His fisher’s coat - His upper or outer garment or tunic, in distinction from the inner garment or tunic which was worn next the skin. In the case of Peter it may have been made of coarse materials such as fishermen commonly wore, or such as Peter usually wore when he was engaged in this employment. Such garments are common with men of this occupation. This outer garment he probably had laid aside.
He was naked - He was undressed, with nothing on but the undergarment or tunic. The word does not require us to suppose a greater degree of nakedness than this. See the Mark 14:51 note; also 1 Samuel 19:24 note.
Did cast himself into the sea - With characteristic ardor, desirous of meeting again his Lord, and showing his affection for him.