Mark 13:30-34
Jesus' Return
30 I tell you the truth, this generation will certainly not pass away until all these things have happened. 31 Heaven and earth will pass away, but my words will never pass away.
32 "No one knows about that day or hour, not even the angels in heaven, nor the Son, but only the Father. 33 Be on guard! Be alert! You do not know when that time will come. 34 It's like a man going away: He leaves his house and puts his servants in charge, each with his assigned task, and tells the one at the door to keep watch.
Jesus tells us about the end of age...He tells us He will return at the end of ages...
What is interesting is Jesus knows all things, yet He does not know when He will return to earth...Only God the Father knows this fact...
St. Mark, the author, could have wrote that the Son and Father both knew, but he did not...He did not because verse 32 was what Jesus said and others heard...
Jesus is telling us no one can predict, when He will return...And He is telling us to be prepared and ready at all times, for His return will come when we do not expect it...