4 And there appeared to them Elijah with Moses, who were talking with Jesus. 5 Then Peter said to Jesus, "Rabbi, it is good for us to be here; let us make three dwellings, one for you, one for Moses, and one for Elijah." 6 He did not know what to say, for they were terrified. 7 Then a cloud overshadowed them, and from the cloud there came a voice, "This is my Son, the Beloved; listen to him!" 8 Suddenly when they looked around, they saw no one with them any more, but only Jesus. 9 As they were coming down the mountain, he ordered them to tell no one about what they had seen, until after the Son of Man had risen from the dead. 10 So they kept the matter to themselves, questioning what this rising from the dead could mean. 11 Then they asked him, "Why do the scribes say that Elijah must come first?" 12 He said to them, "Elijah is indeed coming first to restore all things. How then is it written about the Son of Man, that he is to go through many sufferings and be treated with contempt? 13 But I tell you that Elijah has come, and they did to him whatever they pleased, as it is written about 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.