Luke 9:31

Who appeared in glory
In a very glorious manner, in most divine and beautiful forms to Christ, and to his disciples:

and spake of his decease, which he should accomplish at Jerusalem;
the word, rendered "decease", is "Exodus", the name of the second book of Moses; so called from the departure of the children of Israel out of Egypt, it gives an account of; and which departure is expressed by this word, in ( Hebrews 11:22 ) and to which the allusion is here. Death is a departure out of this world, and goes by this name, ( 2 Peter 1:15 ) and so here it signifies Christ's death, or exit, which he was to make at Jerusalem; and Moses and Elias talk with him about this; the nature, manner, use, and near approach of it; and to which they might encourage him, as man. The sufferings and death of Christ were what Moses and the prophets had foretold; and these two speak of the same things now; and which must serve to confirm what Christ a few, days ago had showed his disciples, that he must go to Jerusalem, and there suffer and die. Dr. Lightfoot thinks that the ascension of Christ to heaven is contained in the word "Exodus", which was his final departure out of this world, as well as his sufferings and death; and especially if there is any, allusion to the Israelites' departure out of Egypt, which was in victory and triumph; and the rather, because "the time of his receiving up", ( Luke 9:51 ) may be thought to refer to this; and so Moses and Elias conversed with him, not only about, his sufferings and death; but his ascension, and of which also the "Exodus", or going of Elias out of this world to heaven, which was by a translation and ascension, was a figure. Some render this word, "Expedition", and think it refers to the whole affair of the redemption of Christ's people by him, from the bondage of sin, Satan, and the law, by his sufferings and death; of which the deliverance of the people of Israel out of Egypt was a lively representation: an expedition which Moses was sent upon, and accomplished: but now the discourse turns upon an expedition of greater importance, which shortly was to be accomplished at Jerusalem, where Christ was to be arraigned, and condemned, and then suffer without the gates of it, in order to obtain eternal redemption for the whole Israel of God.