What does Matthew 17:4 mean?
Peter, James, and John are witnessing something that is beyond words: Jesus has been "transfigured" before their eyes into a radiant appearance as the Son of God in heaven. He stands talking to two of the greatest heroes of Israel: Moses and Elijah (Matthew 17:1–3).In this holiest of moments, Peter's choice to speak is awkward and inappropriate. In fact, he will be literally interrupted by a voice from heaven (Matthew 17:5). It also reveals he only shallowly understands that Jesus is the Christ, the Son of the living God (Matthew 16:16, 21–23). Mark's account puts Peter's gawky response in relatable terms: he did not know what to say (Mark 9:6). Luke is somewhat less kind, pointing out that Peter did not know what he was saying (Luke 9:33). Peter recognizes the astounding nature of what is happening. Though he is terrified, he feels he must respond with some act of worship. That impulse was not wrong, but the specific action Peter suggests misses the point.
The Gospels portray Peter as a man of extremes: at times the best, other times the worst of the Twelve. He has the faith and boldness to walk on the water as Jesus does, and the weakness to see the waves and sink (Matthew 14:28–31). He accurately declares Jesus is the Christ, the Son of the living God, only to be harshly scolded for trying to rebuke Jesus' teaching (Matthew 16:13–19, 21–23). Peter's boldness and enthusiasm repeatedly reveal both a good heart and a level of recklessness. Many readers are drawn to Peter, because so many of us are very much like him.
Peter tells Jesus that it is good he and James and John are present. He offers to make three tents, one each for Jesus, Moses, and Elijah. Why tents? Peter possibly sees a fulfillment of Israel's Feast of Tabernacles, where Jewish people would make tents to remember God's provision and to look forward to the coming of the kingdom. It makes some sense as a worshipful response, but Peter made the mistake of making Jesus equal to Moses and Elijah. The voice of God the Father from heaven will rebuke Peter and correct his error.