At lunch today the question was asked, Why the Transfiguration?
Here are some ideas:
Parallel passages to look at here are Mt 17 1-9, Mk 9 1-9, Lk 9 28-35
Jesus was with Moses and Elijah -representing the Law and the Prophets.
Separate readings from the Law and the Prophets were part of every Synagogue service Acts 13 15.
Jesus regards the Law and the Prophets as the main witnesses to God Matt 5 17, Matt 7 12.
Notice that neither Moses nor Elijah had a known grave and both had talked to God on a high mountain Ex 31 8, 1 Ki 19 9.
At this time they talked to Jesus about the details of his ‘departure’ (lit. ‘Exodus’) which Jesus was to ‘bring to fulfillment in Jerusalem”. Lk 9 31
This presumably would have included some detail which is not present in Scripture. As Jesus had laid aside the use of his Omniscience (All-Knowingness) as God, he only knew a. What Scripture says, b. What the Holy Spirit revealed to Him (in the same way the Holy Spirit would reveal to us).
This event opens another avenue of communication for Jesus to receive revelation from his Father.
So Jesus is learning of things which will happen at his death and Resurrection, things which he couldn’t learn from Scripture, because that amount of detail wasn’t in there.
(Why not? I would guess God has good reasons NOT to reveal some things to all readers. Only what WE need is in there – and there were presumably some things which Jesus needed to know that we don’t need to know.)
From this event we also can note:
As the three disciples were to be witnesses at his crucifixion, this view of Jesus’ glory is preparation.
The Father verifies Jesus’ sonship to the disciples.
We learn that the ‘dead’ are not asleep, or annihilated, but are conscious. They are aware of events in the Spiritual World, and it would seem from this story, in the Natural World too.
The ‘dead’ know each other, and are recognisable.