Nahj al-Balāgha, no. 375

He ordained livelihoods [3] with plenty and with paucity. He distributed them narrowly as well as profusely. He did it with justice to test whomever He desired, with prosperity or with destitution, and to test through it the gratefulness or endurance of the rich and the poor. Then He coupled plenty with misfortunates of destitution, safety with the distresses of calamities and pleasures of enjoyment with pangs of grief. He created fixed ages and made them long or short and earlier or later, and ended them up with death. He had made death capable of pulling up the ropes of ages and cutting them asunder.