In Matthew 24:44 Jesus said in His Olivet Discourse, “Therefore be ye also ready: for in such an hour as ye think not the Son of man cometh.” This is the first recorded occasion of those particular words coming from Jesus. The words to which I refer are “be ye also ready.”
Readiness for the Lord’s return and a warning not to become apathetic is a common theme from Jesus. The identical verbiage is in the Luke account (Luke 12:40). The New Testament teaches the imminence of Christ’s return. Paul in his first epistle to the Thessalonian church writes in 1 Thessalonians 5:2, “For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.” The point is that a thief will not announce his coming, so you’ve got to be ready always for his coming. In the same way, we should keep ourselves ready for the Lord’s return.
A few verses later, Paul writes: “But ye, brethren, are not in darkness, that that day should overtake you as a thief.” Paul expresses incredulity at the idea that those believers in the first century should not be making themselves ready for the Lord’s return, referred to as the Day of the Lord. We are far closer now. In Revelation 3:3, Jesus says: “If therefore thou shalt not watch, I will come on thee as a thief, and thou shalt not know what hour I will come upon thee.”
Part of being ready is watching, which expresses anticipation. The Lord’s return is imminent, which means that, one, no one knows the day or the hour of His return, and, two, it could happen any moment and very quickly so that no time exists for preparation.