John 12:49

ὅτι. Because. It introduces the reason why one who rejects Christ’s word will be judged by His word;—because that word is manifestly Divine in origin. With ἐξ ἐμαυτοῦ, out of Myself as source, without commission from the Father, comp. ἀπ' ἐμαυτοῦ, John 5:30; John 7:17; John 7:28; John 8:28; John 8:42; John 10:18; John 14:10.

αὐτός. Himself (and none other) hath given Me commandment (see on John 3:35; John 10:18), what I should say and how I should say it; εἴπω refers to the doctrine, λαλήσω to the form in which it is expressed (see on John 8:43, and comp. John 14:10; John 16:18).