Read John 12:49 Using Other Translations
For I have not spoken of myself; but the Father which sent me, he gave me a commandment, what I should say, and what I should speak.
For I have not spoken on my own authority, but the Father who sent me has himself given me a commandment--what to say and what to speak.
I don’t speak on my own authority. The Father who sent me has commanded me what to say and how to say it.