John Chrysostom — as excerpted in the Catena Aurea on John 17:9-13

“(Hom. lxxxi. 1) He often repeats, Thou hast given Me, to impress on them that it was all according to the Father’s will, and that He did not come to rob another, but to take unto Him His own. Then to shew them that this power1 had not been lately received from the Father, He adds, And all Mine are Thine, and Thine are Mine: as if to say, Let no one, hearing Me say, Them which Thou hast given Me, suppose that they are separated from the Father; for Mine are His: nor because I said, They are Thine, suppose that they are separate from Me: for whatever is His is Mine.”