John Wesley on John 15:26

When the Comforter is come, whom I will send from the Father, the Spirit of truth, who proceedeth from the Father, he shall testify of me - The Spirit's coming, and being sent by our Lord from the Father, to testify of him, are personal characters, and plainly distinguish him from the Father and the Son; and his title as the Spirit of truth, together with his proceeding from the Father, can agree to none but a Divine person. And that he proceeds from the Son, as well as from the Father, may be fairly argued from his being called the Spirit of Christ, 1Pet 1:11; and from his being here said to be sent by Christ from the Father, as well as sent by the Father in his name.