Expositor's Bible Commentary Commentary Matthew 24:42

"Watch therefore: for ye know not on what day your Lord cometh." — Matthew 24:42 (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.