John 14:15

Christ not only proposes such things to them as were the matter of their comfort, but here promises to send the Spirit, whose office it should be to be their Comforter, to impress these things upon them. I. He premises to this a memento of duty (Joh 14:15): If you love me, keep my commandments. Keeping the commandments of Christ is here put for the practice of godliness in general, and for the faithful and diligent discharge of their office as apostles in particular. Now observe, 1. When Christ is comforting them, he bids them keep his commandments; for we must not expect comfort but in the way of duty. The same word (parakaleō) signifies both to exhort and to comfort. 2. When they were in care what they should do, now that their Master was leaving them, and what would become of them now, he bids them keep his commandments, and then nothing could come amiss to them. In difficult times our care concerning the events of the day should be swallowed up in a care concerning the duty of the day. 3.

— Matthew Henry's Concise Commentary (public domain)

If ye love me, keep my commandments. And I will pray the Father, &c.--This connection seems designed to teach that the proper temple for the indwelling Spirit of Jesus is a heart filled with that love to Him which lives actively for Him, and so this was the fitting preparation for the promised gift. he shall give you another Comforter--a word used only by John; in his Gospel with reference to the Holy Spirit, in his First Epistle (Jo1 2:1), with reference to Christ Himself. Its proper sense is an "advocate," "patron," "helper." In this sense it is plainly meant of Christ (Jo1 2:1), and in this sense it comprehends all the comfort as well as aid of the Spirit's work. The Spirit is here promised as One who would supply Christ's own place in His absence. that he may abide with you for ever--never go away, as Jesus was going to do in the body.

— Jamieson-Fausset-Brown Commentary (public domain)