But pray ye that your flight be not in the winter, neither on the {h} sabbath day:

(h) It was not lawful to take a journey on the sabbath day; Josephus, book 13.

People's New Testament

24:20 Be not in the winter. Because the streams were then impassable torrents from the heavy rains and the weather cold and wet, hard on homeless people.

Neither on the sabbath. Because then the gates of the city were closed, preventing departure. History tells us that the army of Cestius Gallus enclosed Jerusalem in A.D. 67, then deterred by its strength, retired to Caesarea. This was the signal for which the church waited, and it then fled beyond the Jordan.

Wesley's Notes

24:20 Pray ye that your flight be not in the winter - They did so; and their flight was in the spring. Neither on the Sabbath - Being on many accounts inconvenient; beside that many would have scrupled to travel far on that day. For the Jews thought it unlawful to walk above two thousand paces (two miles) on the Sabbath day.

Matthew Henry's Concise Commentary

24:4-28 The disciples had asked concerning the times, When these things should be? Christ gave them no answer to that; but they had also asked, What shall be the sign? This question he answers fully. The prophecy first respects events near at hand, the destruction of Jerusalem, the end of the Jewish church and state, the calling of the Gentiles, and the setting up of Christ's kingdom in the world; but it also looks to the general judgment; and toward the close, points more particularly to the latter. What Christ here said to his disciples, tended more to promote caution than to satisfy their curiosity; more to prepare them for the events that should happen, than to give a distinct idea of the events. This is that good understanding of the times which all should covet, thence to infer what Israel ought to do. Our Saviour cautions his disciples to stand on their guard against false teachers. And he foretells wars and great commotions among nations. From the time that the Jews rejected Christ, and he left their house desolate, the sword never departed from them. See what comes of refusing the gospel. Those who will not hear the messengers of peace, shall be made to hear the messengers of war. But where the heart is fixed, trusting in God, it is kept in peace, and is not afraid. It is against the mind of Christ, that his people should have troubled hearts, even in troublous times. When we looked forward to the eternity of misery that is before the obstinate refusers of Christ and his gospel, we may truly say, The greatest earthly judgments are but the beginning of sorrows. It is comforting that some shall endure even to the end. Our Lord foretells the preaching of the gospel in all the world. The end of the world shall not be till the gospel has done its work. Christ foretells the ruin coming upon the people of the Jews; and what he said here, would be of use to his disciples, for their conduct and for their comfort. If God opens a door of escape, we ought to make our escape, otherwise we do not trust God, but tempt him. It becomes Christ's disciples, in times of public trouble, to be much in prayer: that is never out of season, but in a special manner seasonable when we are distressed on every side. Though we must take what God sends, yet we may pray against sufferings; and it is very trying to a good man, to be taken by any work of necessity from the solemn service and worship of God on the sabbath day. But here is one word of comfort, that for the elect's sake these days shall be made shorter than their enemies designed, who would have cut all off, if God, who used these foes to serve his own purpose, had not set bounds to their wrath. Christ foretells the rapid spreading of the gospel in the world. It is plainly seen as the lightning. Christ preached his gospel openly. The Romans were like an eagle, and the ensign of their armies was an eagle. When a people, by their sin, make themselves as loathsome carcasses, nothing can be expected but that God should send enemies to destroy them. It is very applicable to the day of judgment, the coming of our Lord Jesus Christ in that day, 2Th 2:1. Let us give diligence to make our calling and election sure; then may we know that no enemy or deceiver shall ever prevail against us.