When the Helper comes, whom I will send to you from the Father, that is the Spirit of truth who proceeds from the Father, He will testify about Me. John 15:26, NASB.
It is to your advantage that I go away; for if I do not go away, the Helper will not come to you; but if I go, I will send Him to you. And He, when He comes, will convict the world concerning sin and righteousness and judgment. John 16:7, 8, NASB.
As they move toward the cross on their last evening with Jesus, the disciples are bewildered and grief-stricken. He keeps telling them that He will soon depart from them to a place that they could not go. But after they lost Him, what were they to do?
It is in that context that Jesus again tells them that He will send the Holy Spirit to be with them and guide them in their lives and ministry. They probably didn't understand the greatness of the gift of the Spirit on that discouraging evening. But after Pentecost they would.
In today's passage Jesus tells us four things about the work of the Holy Spirit. The first is that He will testify about Jesus. Here we have a most interesting fact. Of the three members of the divine Godhead we know least about the Spirit. Why? Because while Jesus came to demonstrate the nature and character of God and while the Spirit has inspired the whole New Testament to help us know Jesus, no one has filled in our knowledge of the Holy Spirit, the third member of the Trinity. As a result, some are tempted to think of Him as less important or less divine than the Father and the Son. But that is not the teaching of Scripture.
The good news is that on His last evening with His disciples Jesus provides us with a glimpse of the work of the Spirit in our lives. Not only does the Spirit testify of Jesus and help us understand His life and teaching, but He also convicts us of sin. That function is absolutely central to the plan of salvation, since without a clear sense of our sins and shortcomings we will feel no need of a Savior. Paul is quite clear that in the process of revealing to us our sin the Spirit uses God's law as the ideal model of the character traits and actions that He desires His followers to exhibit in their life (see Rom. 7:7).
On the opposite side of the convicting-of-sin coin is the Spirit's function of leading us to Jesus for forgiveness and a pattern of life. And closely related to those two functions is the Spirit's conviction of judgment for those who reject Jesus.
Today we need to thank Jesus again for the gift of the Helper. Without the Spirit a walk with Jesus would be impossible. The Holy Spirit is the dynamic force in our salvation.