greek syntax principle 19

When αυτος is nominative and in predicate position, it functions as an intensive pronoun. cf. BBG 12.10.

αὐτὸς γὰρ Ἰησοῦς ἐμαρτύρησεν ὅτι προφήτης ἐν τῇ ἰδίᾳ πατρίδι τιμὴν οὐκ ἔχει. (John 4:44)

For Jesus Himself, testified…