Luke 21:34-35

“But take heed to yourselves, lest it happen that your hearts be overcharged with surfeiting, and drunkenness, and cares of this life, and that day come on you suddenly as a snare, for so will it come on all those who dwell on the face of all the earth.”

In view of this certainty of the fulfilment of His words they must be sure that they keep a watch on their ways and are not caught out by their being too deeply involved in partying, and drunkenness and the affairs of life (a reminder that although Jesus ate and drank with public servants and sinners, He did not see their lifestyle as acceptable). If their hearts are taken up with such things then that day will come on them like a snare and a trap, in the same way as it will come on all who dwell on the face of the whole earth who are not believers and therefore are unready.