Augustine of Hippo
Catena Aurea · Johannesevangelium 14
If ye love me, keep my commandments. And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever; Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.
(Tract. lxxiv. c. 1) But when the love of God is shed abroad in our hearts by the Holy Ghost which is given unto us, (Rom. 5:6) how shall we love and keep the commandments of Christ, so as to receive the Spirit, when we are not able to love or to keep them, unless we have received the Spirit? Does love in us go first, i. e. do we so love Christ and keep His commandments as to deserve to receive the Holy Spirit, and to have the love of God the Father shed abroad in our hearts? This is a perverse opinion. For he who does not love the Father, does not love the Son, however he may think he does. (c. 2). It remains for us to understand, that he who loves has the Holy Spirit, and by having Him, attains to having more of Him, and by having more of Him, to loving more. The disciples had already the Spirit which our Lord promised; but they were to be given more of Him: they had Him secretly, they were to receive Him openly. The promise is made both to him who has the Spirit, and to him who has Him not; to the former, that he shall have Him; to the latter, that He shall have more of Him.