The disciples did expect Christ to return "soon". It was St. Peter who reminded them:
"But do not ignore this one fact, beloved, that with the Lord one day is as a thousand years, and a thousand years as one day. The Lord is not slow about his promise as some count slowness, but is forbearing toward you, not wishing that any should perish, but that all should reach repentance. . . . Since all these things are thus to be dissolved, what sort of persons ought you to be in lives of holiness and godliness, waiting for and hastening the coming of the day of God, because of which the heavens will be kindled and dissolved, and the elements will melt with fire! But according to his promise we wait for new heavens and a new earth in which righteousness dwells. Therefore, beloved, since you wait for these, be zealous to be found by him without spot or blemish, and at peace"
(2 Pet. 3:8–14).