15-16. Hutcheson argues that this passage (through verse 18 actually) tells us of the magnificence of Christ; that He has more magnificence than John (15), believers (16), Moses (17), and all men (18). Godet says that v. 16 is grace, v. 18 is truth, and v. 17 connects grace to truth.
15. Morris notes that “People were humble about their own generation and really thought that their fathers were wiser than they—incredible as this may sound to our generation.” John therefore indicates here a reversal of the normal pattern. The word “testifies” is in present tense, indicating that this doctrine is still in full force (Calvin). Ryle notes that it was John’s habitual testimony. Lenski calls this verse a riddle (not in the sense of incomprehensible, but in the sense of the form of a riddle). “The one who came after me has stepped ahead of me” (Augustine). Beasley-Murray notes that the status accords with priority in time. John understood Christ’s pre-existence. Some people tend to think ill of John’s level of knowledge, but John did know this (Ryle). Plainly the last clause of the riddle explicitly states the pre-existence of Christ. Christ is both before and after John, and therefore ranks higher than John.
16. Is John the Baptist still speaking, or is this John the evangelist? Who is the “we?” Probably the congregation (Bultmann).The “all” hints at the infinite resources (Morris). On the phrase “Grace for grace,” does John mean NT vs. OT, or grace piled on top of grace? Given verse 17, the former is more likely, as long as vs 17 is not understood in an adversarial way. Actually, both could be understood together. Keddie says that the grace acts “Like waves of the sea.” Kostenberger notes “It is as though, when the incarnation finally arrived, full of covenant love, the OT stood up and cheered.”
17-18. The connection of the two verses is well stated by Augustine: “And in case anyone should say, ‘Did not both grace and truth come about through Moses, who saw God?’ he immediately added, no one has ever seen God.” Moses did not have the law in and of himself, but Jesus does have grace and truth in and of Himself (Bengel).
17. Notice the contrast between “given” and “came” (Tasker). Carson says that there is nothing in this verse that requires antithesis. Schnackenburg notes the eschatological character of salvation pointed out in this verse. The revelation of Christ surpassed that of Moses because Moses did not really see God. Only Jesus has seen God (Kruse).
18. The first phrase of this verse “denies that God is directly accessible to men. At the same time it assumes that it is natural for man to wish to see God and to be able to approach him” (Bultmann). Only God can reveal God (Lindars). On the “bosom” of the Father: “So intimately close to the Father that He is reliably informed about the decisions of His Father’s heart” (Luther). Bultmann says it this way: “it stresses the absoluteness and sufficiency of the revelation, because the Revealer as the Son of the divine love stands in perfect communion with the Father.” Note the word “exegesato.” It means “narration” or “exegesis.” Jesus is the “exegesis” of the Father. He explains the Father to us.