'Alert' in the Bible

“Take heed, keep on the alert; for you do not know when the appointed time will come.

It is like a man away on a journey, who upon leaving his house and putting his slaves in charge, assigning to each one his task, also commanded the doorkeeper to stay on the alert.

Therefore, be on the alert—for you do not know when the master of the house is coming, whether in the evening, at midnight, or when the rooster crows, or in the morning—

What I say to you I say to all, ‘Be on the alert!’”