Albert Barnes Commentary Matthew 24:43

"But know this, that if the master of the house had known in what watch the thief was coming, he would have watched, and would not have suffered his house to be broken through." — Matthew 24:43 (ASV)

But know this, if a man knew the hour, or about the hour, when a robber would come, he would be ready for him. So you do not know the exact hour, but you know it is near, when the Son of Man will come. He will come suddenly, as a thief comes, without giving previous warning (1 Thessalonians 5:2; 2 Peter 3:10; Revelation 3:3; Revelation 16:15).

Goodman. See Barnes on Matthew 20:11.

Thief. A robber. A thief, with us, means one who takes goods without doing violence—secretly, silently. The original word means one who does it by housebreaking, or by highway violence (Luke 10:30).

Broken up. Broken into—either by the doors or windows.

In what watch. In which of the four quarters of the night. See Barnes on Matthew 14:25.