It is the spiritual power of carrying a burden, being patient and forbearance.
This power is necessary for having patience and firmness. The virtue of patience is obvious. Those who can acquire this high virtue and has endurance can make himself a target against troubles for the sake of good and pious deeds and when a trouble hit him by divine ordinance he never complaints about it.
The opposite of endurance is impatience, weakness and hastiness.
Carrying the burden caused by friends and being tolerant against the errors as a result of human nature is a praiseworthy charactersitics of enduring people.
Those large-hearted ones have many friends, less enemy, they fell relieved and their lives are long. Intolerant, restless people are the opposite of it. Their friends are less, enemy are more and they can not free themselves from anxiety.