A common refrain in sermons (and I've used this myself!) on the Transfiguration is that Jesus is being shown to be "the Word."

Historically, Jesus referred to the Scripture as "the Law and the Prophets," referencing a common idiom of the time. Of these,

• Moses is clearly the "Lawgiver," in that he is identified with the Covenant most closely.
• Elijah is the "Prophet," the first in a line and the prototype of many.

By appearing with "the Law" (Moses) and "the Prophets" (Elijah), Jesus is shown to be fufilling all of Scripture.

John 5:39 You study the Scriptures diligently because you think that in them you have eternal life. These are the very Scriptures that testify about me...

A common refrain in sermons (and I've used this myself!) on the Transfiguration is that Jesus is being shown to be "the Word."

Historically, Jesus referred to the Scripture as "the Law and the Prophets," referencing a common idiom of the time. Of these,

• Moses is clearly the "Lawgiver," in that he is identified with the Covenant most closely.
• Elijah is the "Prophet," the first in a line and the prototype of many.

By appearing with "the Law" (Moses) and "the Prophets" (Elijah), Jesus is shown to be fufilling all of Scripture.