A.T. Robertson Commentary John 7:18

"He that speaketh from himself seeketh his own glory: but he that seeketh the glory of him that sent him, the same is true, and no unrighteousness is in him." — John 7:18 (ASV)

From himself (αφ' εαυτου). This kind of teacher is self-taught, pushes his own ideas, presses his own claims for position and glory, "blows his own horn" as we say. Jesus is the other type of teacher, seeks the glory of the one who sent him, whose herald and ambassador he is.

The same (ουτος). "This one."

Unrighteousness (αδικια). Old word from αδικος (α privative and δικη). Here in contrast with "true" (αληθης). See 2 Thessalonians 2:10; 1 Corinthians 13:6 for the deceit of unrighteousness in contrast with truth as here.