Pray that your flight may not be in winter or on a Sabbath.
Matthew 24:20

In the winter because it’s cold and dangerous to travel. On the Sabbath for several possible reasons:
1. You might not be able to carry burdens, including your possessions and materials necessary for the journey
2. Many will limit themselves to a “Sabbath-day’s journey” and so not be able to travel far enough to escape the trouble.
3. Fleeing an invading army implies traveling far, quickly, and through inhospitable terrain. In other words, a journey that will necessarily be laborious beyond normal.