Mark 6:30-31 - "And the apostles gathered themselves together to Jesus, and told him all things, both what they had done, and what they had taught. And he said unto them, “Come apart into a desert place, and rest a while,” for there were many coming and going, and they had no freedom even to eat."
Some Christians rarely or never seem to do any kind of service for the Lord that is likely to put them in any danger of needing any period of rest and refreshment from it.
Others think that exhausting oneself beyond the point of usefulness and being able to operate properly is a work of special merit and that rest is only for the weak and lazy.
Jesus teaches us a happy medium between these two errors. Our commission is not to spare ourselves and bury our talent in the ground whilst doing nothing to advance the Lord's kingdom; neither is it to burn out in a flash like a firework. It is to gradually wear out, according to the years given to us, giving our strength for Christ and pacing ourselves to run the race with perseverance until we finish and receive the crown.