John Chrysostom — as excerpted in the Catena Aurea on John 16:12-15

“(Hom. lxxviii) Having said then, Ye cannot bear them now, but then ye shall be able, and, The Holy Spirit shall lead you into all truth; lest this should make them suppose that the Holy Spirit was the superior, He adds, For He shall not speak of Himself but whatsoever He shall hear, that shall He speak.”