As John speaks of the fullness we have received, he adds "and grace for grace." Does this not expand the meaning of "fullness" and give more understanding of "glory"? Our concept of grace is often much more meager than God's. We may view grace only as mercy, or perhaps "unmerited favor." While I believe these ideas are included, grace is much broader in scope.
Along with the passage in John 1:14-17, consider this: "And with great power the apostles gave witness to the resurrection of the Lord Jesus. And great grace was upon them all" (Acts 4:33). "When he came and had seen the grace of God, he was glad, and encouraged them all that with purpose of heart they should continue with the Lord" (Acts 11:23). "So now, brethren, I commend you to God and to the word of His grace, which is able to build you up and give you an inheritance among all those who are sanctified" (Acts 20:32). "So we urged Titus, that as he had begun, so he would also complete this grace in you as well. But as you abound in everything--in faith, in speech, in knowledge, in all diligence, and in your love for us--see that you abound in this grace also" (2 Corinthians 8:6-7).
From these scriptures we see that grace can be expressed and seen in many ways. Grace is ability from God to meet responsibility in the kingdom of God. Grace brings an expression of the character and nature of God in human vessels. All have received some measure of grace, and this grace can be increased and developed. One grace builds on another, and grace in one person is used to build and expand grace in another. Grace is given in different measures, but each one has been given grace to perform that which God requires. An expression of grace brings glory to God, for we realize the source. Because the source is God himself, there is no limit to grace, and experiencing the grace of God to do what is humanly impossible always brings us to a new place in God where we can experience even more of His grace.
When John described the glory of God that was revealed through Jesus, the first word he used was "grace." Does this help to answer the question we began with? Jesus said that He has given us the glory the Father gave Him. That glory was expressed in grace, and in Jesus there was no limit to that grace. He was God revealed in human form. He moved in union with the Father and under the direction of the Holy Spirit. The Father, Son, and Holy Spirit are one, so there was one expression of God at all times and in every situation.
What is the glory Jesus has given us? Did He not give Himself at Calvary? Has He not given us the Holy Spirit? Did He not open the door that we may know union with God? Have we not been brought into fellowship with God, whereby He calls us friends, and all things He receives from the Father He makes known to us (John 15:15)? Do we not now move by the ability (grace) that God provides, and not our own ability? Is there any limit to what God can do? If there is no limit to what God can do, is there any limit to what God can do in us? And can all of this be described by anything other than "glory"? Hallelujah! What a glorious salvation we have in Jesus our Lord!