Expositor's Bible Commentary 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)

The first parable teaches both the unexpectedness of the return of “your Lord” and the church’s willingness to call Jesus “the Lord,” a religious title hitherto reserved by the Jews for God himself (1 Corinthians 12:3; 2 Thessalonians 2:2; 2 Thessalonians 8:21). It might be better to take “understand” (GK 1182) as an indicative (“you know”) rather than an imperative: the disciples know that an owner of a house would be awake and watching if he knew when a thief was coming. Since no one knows at what “watch” a thief might strike, constant vigilance is required. Similarly, we must also always be ready because in this one respect—the unexpectedness of his coming—the Son of Man resembles a thief.