There is always a degree of finagling that goes on when any biblical text is called upon to support a doctrine or understanding of the church.
When that doctrine, in this case a way of understanding God, is as complex and counter intuitive as the Trinity, much is demanded of the preacher's ingenuity. And when a complex doctrine, the Trinity, is little thought about by those in the pews, striving to be succinct, clear, evocative, and scriptural, creates considerable difficulty.
That reality having been described let us dig into this short text from John's gospel with some hope that we preachers may be inspired and inspiring.
In this passage Jesus continues the farewell speech that extends from 13:31-17:26, with only a few strategic interruptions from the eleven who remained with Jesus after Judas had gone out from the group gathered for the last supper. The questions from the disciples (Simon Peter in 13:36-37; Thomas in 14:5; Philip in 14:8; the disciples in 16:17-18; the disciples in 16:28-30) not only provide literary impetus for Jesus to speak, but suggest questions in the hearts and minds of all disciples since they seek to understand their Lord and their lives. "Where are you going?" (13:36) "Lord, we don't know where you are going. How can we know the way?" (14:5) "Lord, show us the father." (14:8) Jesus speaks words of promise and reassurance to the confused and frightened followers. Among those words are those we hear from Holy Trinity Sunday.
These four verses are loaded with the vocabulary of speaking and announcing (six times). It is safe to say that Jesus is passionately interested in communication in these verses, more exactly, reliable communication of truth for the sake of guidance (verse 13). He has already promised the eleven that the "Advocate," the Holy Spirit" would come from the Father after his own departure (see 14:25; 15:26; 16:7). He has already pointed out that he must "leave" for the Advocate to come, that it will be much to the advantage of disciples that the Advocate should come (16:7) for finally the truth about sin and righteousness will be made clear. Jesus' disciples are to trust the Advocate, also called the Holy Spirit, and spirit of truth because the coming Advocate comes from the Father ("another Advocate, 14:16) and will remain forever because the Advocate will testify to Jesus (15:26). So many repetitions of the promised one, the Spirit who is to come, help us hear that Father, Advocate/Spirit, and Jesus will all speak the same truth about relationship with God.
This is perhaps the most important power in affirming the Trinity—that the witness of Jesus is a true witness to the power and will, the glory in a word, of the Father. The witness of the Advocate that comes after Jesus will speak the same truth. The Holy Spirit is a reliable leader in the way of truth, precisely because the Spirit witnesses to Jesus who shares all things with the Father. The Trinity helps the disciples in John and in our assemblies trust that we have indeed seen the Father and can continue to see the Father in our own time and place.
What seems to me both provocative and liberating in Jesus' promise is that he begins by telling the eleven that there are still many things, not just a few, but many things, which he has to say, but that his hearers are simply "not able to bear them" at that time. There is a definite sense that speaking, even of the deepest truths, depends on circumstance, the spirit of one's hearers, and purpose. John makes this clear in Jesus' speech in chapter 16.
This is good news for the disciples. Even though they do not fully understand Jesus, as John makes clear in 16:17-18, the last line of which is "we don't know what he is talking about," reflection for them and for us can lead to encouragement in tough times, times of sadness, and times of confusion.
The future is open. It requires our discernment, our listening, watching for, and trusting that God will continue to reveal Godself through the Spirit of Truth. We, along with the eleven, can trust that the God Jesus has shown us is the God still at work for our illumination and strength to persist. We dare to humbly acknowledge that there may still be truths that we are not able to bear, and that God accompanies us along the way.
We may say with the eleven that we do not understand. But God's sending of the Spirit of Truth is not dependent on our understanding. The spirit will not be taken away from us in the times we are least able to trust, understand, or persevere. For Father, Son, and Spirit of Truth witness to one truth, all of which we cannot see, but all of which we dare to trust is God at work for us, revealing righteousness here and preparing a place suitable for each and all of us in the fullness of God's reign.