Verse 30. - And, behold, there talked with him two men, which were Moses and Elias; literally, there were talking. Evidently these two glorified beings had been conversing with Jesus some time before the three apostles, heavy with sleep, had noticed their presence; wearied and tired, slumber had overtaken them; we are not told how long they slept. The glorious light which environed them and the murmur of voices probably roused them, and in after-days they recounted what, after they were awake, they saw, and something of what they heard.

9:28-36 Christ's transfiguration was a specimen of that glory in which he will come to judge the world; and was an encouragement to his disciples to suffer for him. Prayer is a transfiguring, transforming duty, which makes the face to shine. Our Lord Jesus, even in his transfiguration, was willing to speak concerning his death and sufferings. In our greatest glories on earth, let us remember that in this world we have no continuing city. What need we have to pray to God for quickening grace, to make us lively! Yet that the disciples might be witnesses of this sign from heaven, after awhile they became awake, so that they were able to give a full account of what passed. But those know not what they say, that talk of making tabernacles on earth for glorified saints in heaven.And behold there talked with him two men,.... Of great note and fame:

which were Moses and Elias; the one the giver of the law from God to the people "of Israel", as well as the redeemer of them from Egyptian bondage, and who led them through the wilderness, to the borders of Canaan's land; and the other a prophet famous for his zeal for God, and his worship, and who was translated, soul and body, to heaven: these appeared and talked with Christ on the mount; and what they talked of is mentioned in the following verse; See Gill on Matthew 17:3.