Jesus was very clear to his disciples that he would come again at a future date. His second coming would signal the end of the earth as we know it.
However, he deliberately did not reveal the exact day and time when he would come again.
Why is that?
St. Ephrem provides a possible reason in a commentary on the Diatessaron that is featured in the Office of Readings during Advent:
To prevent his disciples from asking the time of his coming, Christ said: "About that hour no one knows, neither the angels nor the Son. It is not for you to know times or moments." He has kept those things hidden so that we may keep watch, each of us thinking that he will come in our own day.
Jesus frequently urged his disciples to "watch" and prepare themselves for his coming.
These words were not only meant for those who listened to him, but for people of every age.
Anticipation for Jesus' second coming
St. Ephrem continues his commentary on Jesus' choice to withhold the exact day of his coming, pointing out that if we had known that day, we would be less motivated to prepare ourselves:
If he had revealed the time of his coming, his coming would have lost its savor: it would no longer be an object of yearning for the nations and the age in which it will be revealed. He promised that he would come but did not say when he would come, and so all generations and ages await him eagerly.
If Jesus said he would come again in the year 3000, we would be less motivated to "keep watch." Instead, we might say to ourselves, "Jesus won't come in my lifetime, so I don't need to do anything to prepare myself."
Jesus, knowing our hearts better than we know them, knew what to do and didn't tell us the day or hour of his coming.
St. Ephrem ends his reflection by writing, "When the Lord commanded us to be vigilant, he meant vigilance in both parts of man: in the body, against the tendency to sleep; in the soul, against lethargy and timidity. As Scripture says: 'Wake up, you just,' and 'I have risen, and am still with you'; and again, 'Do not lose heart.' Therefore, having this ministry, we do not lose heart."
Let us be vigilant in waiting for the coming of the Lord.