The passage
      v14. John now further develops the theme of the logos. He tells us that the Word is the ultimate disclosure, revelation, of God to humanity. This divine Word which is God, was incarnated (infleshed in a human person) and has taken up residence among his people in a personal way, cf. Ex.25:9. The apostles have personally seen the incarnate Word, God's best-loved Son, they have seen his glory, the glorious shining witness of one who exudes dependable grace. The phrase "grace and truth" actually comes from the Old Testament and is translated in the Greek Old Testament as "mercy and truth". The phrase is used to describe the covenant mercy of God, his gracious constancy, his dependable kindness toward his people. Jesus, the incarnate Word, radiates this kindness, this grace, a radiance that far exceeds the shining glory of the divine presence that once filled the temple.
      v15. In this aside, John makes the point that not only have the apostles seen the incarnate Son, but the Baptist has also seen him and has testified that although the ministry of Jesus followed him, Jesus takes precedence over him.
      v16. The incarnate Word whom the Baptist gives witness to, takes precedence over the Baptist because Jesus is a limitless source of dependable grace, not just for the apostles, but for everyone. God's grace in Christ transcends his kindness in the past and so certainly transcends the ministry of the Baptist. The NIV has one grace (a kindness of God) piling up on another, but it is more likely one grace replacing another.
      v17. The law, given through Moses, exhibits God's special kindness toward his historic people Israel, but the dependable grace that comes to us through Jesus totally transcends God's kindness in the past.
      v18. Although no human has ever seen the living God, we have seen something of him in his law, particularly in the interplay between justice and mercy. Yet in Christ, "the Son, the only one", the divine incarnate Son who is intimately associated with the Father, we learn of dependable grace. The living God is displayed (revealed and exegeted) in the enduring merciful loving kindness of Christ. Jesus conveys the idea of grace to us and in that idea we discover God.

God's gracious constancy
      In the Old Testament, God's presence in the temple is described as a glowing mist. This "glory" of the Lord is called the Shekina. When Moses confronted the Lord's glory, his face actually shined. It was such an awesome sight that the people asked Moses to cover his face for they feared to look upon it. As the nation Israel staggered toward its destruction, the glory of the Lord abandoned the temple and so God's people were left with a mere empty building.
      Few believers are mystics, but there are few believers who don't want, even need, to experience the presence of the divine, to see the inner light of God's glory. For myself, I actually climbed a mountain to confront the divine. I was facing one of those testing times and I thought it was about time Jesus made himself known to me. I ended up sitting on a rock fending off a nest of bull-ants. So much for a heightened awareness of the divine. The Lord's glory is not found on the top of a mountain.
      So where do we confront the divine, where do we touch the eternal living God, where do we experience the inner light? John tells us that the apostles saw the glory of the Lord in the incarnate Word, in the person of Jesus who had donned our humanity. They saw in him, gracious constancy. The NIV calls it "grace and truth", but the phrase actually comes from the Old Testament and is used to describe God. He is a God who loves his people with enduring love, enduring mercy and kindness. The point is that this grace now present in Jesus, completely transcends God's kindness in the past. The historic people of Israel knew something of God's loving kindness, particularly in the law, but his enduring grace in Christ transcends all that has gone before. The Baptist saw this grace in Jesus and unquestioningly gave Jesus precedence over him.
      There is something wondrous about God's grace. Jesus reveals the grace of God and in that revelation we witness the glory of God, we confront the divine. The idea of boundless loving mercy and kindness somehow catches up into the presence of the Lord. The idea lifts us up from ourselves; it is transcendent. The dynamism of God's overflowing grace in Christ rests with its active nature. On recognizing the truth we receive it; it acts upon us. God's mercy in Christ washes over us and we are clean, his glory radiates out onto us and we glow.

v15
      Brown and others see this verse as another addition to the original poem, although it is more likely a parenthetical remark serving to link the ministry of the Baptist with that of Jesus. It is not even possible to argue that the prologue is definitely poetry; it is more rightly rhythmic prose.
      marturei (marturew) pres. "testifies" - testified. Historical present tense. The Baptist has already testified to Jesus at the time of writing.
      kekragen (krazw) perf. "he cries out" - has cried out, has testified. The Baptist's testimony in the past continues to impact on the present.
      prowtoV mou hJn "he was before me" - became before me. Precedence is probably the dominant sense. The Baptist's ministry preceded that of Jesus, but this does not mean he takes precedence over Jesus. A temporal sense may also be implied, "before I was born, he already was", NEB. Why the Baptist believed that Jesus took precedence may be explained by his knowledge of Jesus as the preexistent incarnate Word as expounded here in John 1, or more likely in his belief that Jesus was the Messiah.

v16
      oJti "from" - that, because, for. Some manuscripts have kai, "and". Origin and others treat this verse as a continuation of the Baptist's words, "he existed before me because of his fullness we have all had a share." Yet this is unlikely. The incarnate Word whom the Baptist gives witness to, takes precedence over the Baptist for he has kindly allowed us to share in the fullness of his enduring grace.
      plhrwmatoV (a) "fullness" - The fullness, or possibly better, the completeness of Christ's enduring grace.
      hJmeiV panteV "we have all [received]" - humanity, not just the apostles.
      anti "[one blessing] after [another]" - [grace] in place of / in addition to / in return for [grace]. The sense is either: i] the enduring grace of God in the old covenant, the Law, is replaced by that of the incarnate Word; ii] the enduring grace of the incarnate Word is added time and time again, or iii] the enduring grace of the incarnate Word is given in return for faith, etc. Meaning ii] is the one most widely accepted, eg. "grace upon grace", RSV. Both Carson and Brown opt for i] and this does seem likely given that v17 seems to explain in more detail how God's hesed grace in the law is replaced and magnified in Christ.

v17
      edoqh (didwmi) aor. "given" - The law was given as a gift, continuing the sense that it is given in an act of kindness.
      hJ cariV kai hJ alhqeia "grace and truth" - enduring/dependable grace/kindness. Although this descriptive is used of Jesus, John is not implying that the law is devoid of grace. It is simply that God's grace finds its ultimate expression in Christ. Note how the article is used to particularize grace and truth.
      egeneto (ginomai) "[given .....] came" - John's choice of these two verbs implies that the law was given and that grace came "according to the orderly and due course of the divine plan", Westcott. Both emerge from God's kindness, but in Christ, God's kindness reaches its "fullness".