133. Whereby is meant no personal duty, but an indivisible sentence of co-operation. For this does not signify any actual hearing of words, but the unity of will and of power, which exists both in the Father and in the Son. He has stated that this exists also in the Holy Spirit, in another place, saying, “For He shall not speak of Himself, but whatsoever He shall hear, that shall He speak,” S. John xvi. 13. so that we may learn that whatsoever the Spirit says, the Son also says; and whatsoever the Son says, the Father says also; for there is one mind and one mode of working in the Trinity. For, as the Father is seen in the Son, not indeed in bodily appearance, but in the unity of the Godhead, so also the Father speaks in the Son, not with a voice of earth, not with a human sound, but in the unity of Their work. So when He had said: “The Father that dwelleth in Me, He speaketh; and the works that I do, He doeth;” S. John xiv. 10. He added: “Believe Me, that I am in the Father, and the Father in Me; or else believe Me for the very work’s sake.” S. John xiv. 17.