John Calvin on John 15:8

8. In this my Father is glorified This is a confirmation of the former statement; for he shows that we ought not to doubt that God will listen to the prayers of his people, when they desire to be rendered fruitful; for this contributes very greatly to his glory. But by this end or effect he likewise kindles in them the desire of doing good; for there is nothing which we ought to value more highly than that the name of God may be glorified by us. To the same effect is the latter clause, that you may become my disciples; for he declares that he has no one in his flock who does not bear fruit to the glory of God.