In the Upper Room, Jesus reminds the apostles that they already know the Spirit (John 14:17). He says that the Spirit dwells with them and will be in them, a description that points to a wonderful relationship, yet one to be developed even more.
In what ways did they know the Spirit? One way is that they knew him as the Spirit of Truth, the title that Jesus uses of the Spirit in this verse.
The Spirit of Truth had convicted them of their sins and revealed to them truths about Jesus. They had been enabled to follow Jesus as their Master and Lord, even although they had still a lot to learn about him. The promise of Jesus that the Spirit would yet be in them indicated that he would continue to reveal truth to them, and we can see a fulfilment of this role in the way the Spirit enabled some of them to contribute to the New Testament in an inerrant manner.
Each Sunday, our services close with the benediction, taken from 2 Corinthians 13, in which we receive the promise of the communion of the Holy Spirit. Communion indicates personal contact, and personal contact is necessary for true knowledge. In such contact we experience what the other has to share. Each time we hear the benediction, we should have expectant hearts because it contains a promise that the Spirit will give blessings to us.
When we have contact with the Spirit, we discover what he has to share, and his gifts are connected to our experience of salvation. Sometimes he focuses on the Father and his role in salvation; at other times, he focuses on the Son and his role in salvation; and at other times, he focuses on his own role in salvation. And there are times when he conveys such knowledge to us in a combined manner.
It is wonderful to know the Spirit. We can know him individually and we can know him corporately and simultaneously. So when Jesus told his disciples that they knew the Spirit he stated a truth that should make us both thankful and amazed