John 10:14

The second mark of the good shepherd is introduced by a repetition of the announcement: ἐγώ … καλός. And this second mark is not stated in general terms applicable to all good shepherds, but directly of Himself: ἐγώ εἰμι … καὶ γινώσκω τὰ ἐμά, καὶ γινώσκομαι ὑπὸ τῶν ἐμῶν. There is a mutually reciprocal knowledge between Jesus and His sheep. And the existence of this knowledge is the proof that He is the Shepherd. The shepherd's claim is authenticated by his knowledge of the marks and ways of the sheep, and by its knowledge of him as shown in its coming to his voice and submission to his hand. Augustine says: “They sometimes do not know themselves, but the shepherd knows them”.