His apostles had been out preaching and teaching and healing and ministering to the public. And it was Jesus who suggested that they get away from the crowds for a while and rest. So many people were coming and going that they scarcely had time to eat. So Mark tells us they left by boat to a quieter spot. Notice it was Jesus who made this suggestion.
Older pastors can remember when rural churches resented pastors taking vacations.
This was understandable when parishioners were glued to their farms. Cows needed to be milked, eggs needed to be gathered, hogs needed to be fed daily. The family farmer could not afford to hire someone to come in and do the chores while the family flew off to Disney World. So, many rural people resented pastors taking vacations too. There was even a famous poem written that suggested that the devil didn't take a vacation and that it was dangerous for a pastor to take a vacation as well.