But know this: if the master of the house knew at what hour the thief was coming, he would keep watch and would not allow his house to be broken into.
In this saying Jesus uses a figurative comparison to show the necessity of watchfulness. Just as the master of the house, if he knew the moment the thief was coming, would stay awake and guard his house, so also the believer must remain continually alert, because the Lord’s coming will be unexpected. This parable shows that spiritual carelessness can lead to theft—not material theft, but the loss of “spiritual treasures.” Jesus warns that one must not wait for a warning or a sign; the time can always be now. This word also shows the Lord’s mercy: He reveals the secret beforehand so that the believer may live not in ignorance, but in preparedness. To be awake here means to keep the faith, as the master of the house keeps his home.