4 And Elijah appeared to them with Moses, and they were talking with Jesus. 5 Then Peter answered and said to Jesus, "Rabbi, it is good for us to be here; and let us make three tabernacles: one for You, one for Moses, and one for Elijah"-- 6 because he did not know what to say, for they were greatly afraid. 7 And a cloud came and overshadowed them; and a voice came out of the cloud, saying, "This is My beloved Son. Hear Him!" 8 Suddenly, when they had looked around, they saw no one anymore, but only Jesus with themselves. 9 Now as they came down from the mountain, He commanded them that they should tell no one the things they had seen, till the Son of Man had risen from the dead. 10 So they kept this word to themselves, questioning what the rising from the dead meant. 11 And they asked Him, saying, "Why do the scribes say that Elijah must come first?" 12 Then He answered and told them, "Indeed, Elijah is coming first and restores all things. And how is it written concerning the Son of Man, that He must suffer many things and be treated with contempt? 13 But I say to you that Elijah has also come, and they did to him whatever they wished, as it is written of him."
Matthew Henry's Commentary on Mark 9:4-13
Commentary on Mark 9:1-13
(Read Mark 9:1-13)
Here is a prediction of the near approach Christ's kingdom. A glimpse of that kingdom was given in the transfiguration of Christ. It is good to be away from the world, and alone with Christ: and how good to be with Christ glorified in heaven with all the saints! But when it is well with us, we are apt not to care for others, and in the fulness of our enjoyments, we forget the many wants of our brethren. God owns Jesus, and accepts him as his beloved Son, and is ready to accept us in him. Therefore we must own and accept him as our beloved Saviour, and must give up ourselves to be ruled by him. Christ does not leave the soul, when joys and comforts leave it. Jesus explained to the disciples the prophecy about Elias. This was very suitable to the ill usage of John Baptist.