This might be a speculative punt but something struck me as I was reading through Nehemiah 8. That’s the passage where Ezra begins to teach God’s people the Law, The people celebrate the feast of Tabernacles at that point and so they build booths to stay in whilst hearing the Torah taught.
Well, when a few of the disciples witness Jesus’ transfiguration, Peter spaks, without really knowing what he I saying. He suggests that they start making shelters or tents/tabernacles/booths for Jesus, Moses and Elijah. Then God the Father speaks, puts the focus on Jesus as his beloved son and tells the disciples to listen to him. I wonder if Peter’s concern was that with these three wise men of God present that by keeping them there, the disciples would benefit from an opportunity to hear their teaching.
If so, then the Father’s response emphasises that it is not Moses, nor Elijah tha they need to pay attention to, not the Law or the prophets. This isn’t because those things are unimportant. Rather, it is that those are both fulfilled in Christ. If you have The Son then you have the Law and the prophets.
It was Jesus that Peter needed to listen to. It is Jesus that we need to listen to today.