43 But understand this: that had the householder known in what [part of the night, whether in a night or a morning] watch the thief was coming, he would have watched and would not have allowed his house to be undermined and broken through.
44 You also must be ready therefore; for the Son of man is coming at an hour when you do not expect Him. (Matthew 24:42-44) [Amplified Bible].
a. The homeowner and the thief (Matt 24:42-44).
Each of the five parables in Matt 24:42-25:46 deals with some aspect of watchfulness. But watchfulness is not always passive: duties and responsibilities must be discharged by Jesus' followers (Matt 24:45-51), and foresight and wisdom are important (Matt 25:1-13). Responsible living under Jesus' directives is rewarded in the end (Matt 25:4-46).
42-44 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 Jews for God himself (1Cor 12:3; 1Thess 2:2; see also Matt 7:22-23; 8:21). It might be better to take "understand" as an indicative ("you know") rather then 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.
[NIV BIBLE COMMENTARY Volume 2: New Testament].
JESUS IS LORD.