John has a way of relating staggeringly immense truths in a ridiculously succinct manner. “The word was with God, and The Word was God” (1:1)—the diversity and unity of the Godhead in ten words. “In Him was life, and that life was the light of all mankind” (1:4)—the spiritual and moral illumination that Jesus’ life provides humanity in thirteen words. “The Word became flesh and made His dwelling among us” (1:14)—the Incarnation in ten words.
Clearly John wasn’t getting paid by the word.
Another example of such conciseness is in v. 14 where he speaks of Jesus as being “full of grace and truth.” The life of Jesus in five words.

F. F. Bruce makes a convincing case for understanding grace and truth as further defining the glory that was witnessed by John and others (v. 14). The glory they beheld in Christ (as the One who was with God and was God) was that He was full of grace and truth. Bruce connects this to Exodus 33:18ff where Moses asks to see God’s glory and Yahweh replies that He will cause “all of My goodness to pass in front of you” (v. 19). When He shows Moses His glory He says, “The Lord, the Lord, the compassionate and gracious God, slow to anger, abounding in love and faithfulness” (34:6). Jesus’ glory, like that of His Father, is that He is full of grace and truth.
In verse 17 this “grace and truth” is developed further. Moses is still under consideration and the whole of his ministry and the covenant he brought is contrasted to Christ bringing grace and truth. Still, it’s a real mistake to understand John to be saying there was no grace or truth in the first covenant God made with Israel. The sacrificial system, the Day of Atonement, and lots of other things show Israel knew plenty about God’s mercy and forgiveness. David celebrates this aspect of his relationship with God in Psalm 32 and in Psalm 103 the writer speaks of Yahweh removing our transgressions from us “as far as the east is from the west” (v. 12). Likewise, there were all kinds of truth under the old covenant as well, those expressed through the Ten Commandments, the exodus (Yahweh’s power over the gods of Egypt), or creation. No, the law came through Moses and with it a measure of grace and truth—but nothing like what is realized in Christ.
There’s a depth and richness to Jesus as the fullness of grace and truth that can be developed in several directions. In Matthew 5:17ff Matthew presents Jesus as the fulfillment of the Law and the Prophets. In the book of Hebrews the writer’s focus is more on the priestly and sacrificial aspects of the covenant being fulfilled by Christ. In John’s gospel we see in His encounters with people from the woman at the well to the cleansing of the temple to the woman caught in adultery. In all of these instances our soul should sing out—this is the Lord we need!