Mark 13:15
And let him that is on the housetop not go down into the house, neither enter therein, to take any thing out of his house: And let him that is on the housetop not go down into the house, neither enter therein, to take any thing out of his house:
Jesus spoke these words on the Mount of Olives to Peter and James and John and Andrew, who came to Him alone after He had left the temple. They came after the disciples had pointed to the temple's strength and beauty and He had foretold that its buildings would be thrown down with not one stone left upon another. They asked when these things would happen and what would be the sign when all would be fulfilled, of His coming and of the end of the world.
In its immediate setting the command belongs to the moment when the abomination of desolation spoken of by Daniel is seen standing where it ought not, and those in Judea must flee to the mountains. With it stand woe to those with child and nursing in those days and prayer that flight be not in winter, because then comes affliction unequaled since creation. That affliction is followed by false Christs, darkened sun and moon and falling stars, the coming of the Son of man to gather the elect, the lesson of the fig tree, and the command to watch.
The saying mingles the destruction of Jerusalem with the great day of His coming, blending the description of the two great crises in mercy because the disciples could not have endured the future events as He beheld them, leaving them to study out the meaning for themselves. What is said of Jerusalem reaches beyond that event to the final conflagration when the Lord rises to punish the world for iniquity. The discourse was given not for the disciples only but for those who live in the last scenes of this earth's history.
The verse commands utter immediacy of escape: when the warning sign appears and the time to flee comes, the one on the housetop must flee at once toward the mountains without going back down into the house or entering to take anything out. He must not delay even for valuable possessions or belongings, just as the man in the field must not turn back to take his garment, lest he be caught in the destruction. When the sign comes there must be no delay to gather belongings, because people will be driven at once into the mountains.
As part of this discourse it stands as a warning relevant to the destruction of cities full of sin, which may come through earthquakes, fire, or flood, when human possessions and carefully protected buildings cannot withstand God's authority. It warns of a coming crisis requiring immediate escape, so parents in the large cities should get out now to places with room where children can move about and have land to cultivate. There they should educate them in cultivation, teach them to keep the Sabbath, never leave the house without committing the family to God, and set Christ before them as the Saviour who gave His life for the life of the world. The warning shows that sudden events of unknown timing and nature will require readiness and immediate action, so people must prepare day by day.