Mark 13:32-33

The time of the last day: V. 32. But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father. V. 33. Take ye heed, watch and pray; for ye know not when the time is.

With so much information given them, the disciples might have thought that they ought to know the exact date of Christ's second advent, for that would greatly simplify matters. But Christ rejects the idea before it has been voiced.

Of the day when the final judgment will burst upon the world and of the hour of the day when its first indications will come to pass, no person knows; even the angels are ignorant, though they know many of the secrets and mysteries of God.

A what is more, the day is not known to Jesus in His state of humiliation. The Son of God, in His capacity as Savior of men and specifically according to His human nature, has renounced His right to this knowledge, chiefly for the sake of men, lest they be tempted to make inquiries and bother Him with importunate pleadings concerning the day and the hour. Here is a secret which is hidden in the omniscience of the Father.

But that fact brings out Christ's admonition all the more strongly: Be on the lookout, be vigilant, for the exact time is not known upon earth. All the calculations of the various sects as to the exact date of Christ's coming are utterly unreliable vagaries, and those that follow them are just as foolish.