Talmud - Mas. Ta'anith 21a
It is related of Nahum of Gamzu that he was blind in both his eyes, his two hands and legs were amputated and his whole body was covered with boils and he was lying in a dilapidated house on a bed the feet of which were standing in bowls of water in order to prevent the ants from crawling on to him. On one occasion his disciples desired to remove the bed and then clear the things out of the house, but he said to them, My children, first clear out the things [from the house] and then remove my bed for I am confident that so long as I am in the house it will not collapse. They first cleared out the things and then they removed his bed and the house [immediately] collapsed. Thereupon his disciples said to him, Master, since you are wholly righteous, why has all this befallen you? and he replied, I have brought it all upon myself. Once I was journeying on the road and was making for the house of my father-in-law and I had with me three donkeys, one laden with food, one with drink and one with all kinds of dainties, when a poor man met me and stopped me on the road and said to me, Master, give me something to eat. I replied to him, Wait until I have unloaded something from the donkey; I had hardly managed to unload something from the donkey when the man died [from hunger]. I then went and laid myself on him and exclaimed, "May my eyes which had no pity upon your eyes become blind, may my hands which had no pity upon your hands be cut off, may my legs which had no pity upon your legs be amputated, and my mind was not at rest until I added, may my whole body be covered with boils." Thereupon his pupils exclaimed, Alas! that we see you in such a sore plight. To this he replied, Woe would it be to me did you not see me in such a sore plight. Why was he called Nahum of Gamzu? Because whatever befell him he would declare, "this also is for the best".
Once the Jews desired to send to the Emperor a gift and after discussing who should go they decided that Nahum of Gamzu should go because he had experienced many miracles. They sent with him a bag full of precious stones and pearls. He went and spent the night in a certain inn and during the night the people in the inn arose and emptied the bag and filled it up with earth. When he discovered this next morning he exclaimed, This also is for the best. When he arrived at his destination and they undid his bag they found that it was full of earth. The king thereupon desired to put them all to death saying, The Jews are mocking me. Nahum then exclaimed, This also is for the best. Whereupon Elijah appeared in the guise of one of them and remarked, "Perhaps this is some of the earth of their father Abraham, for when he threw earth [against the enemy] it turned into swords and when [he threw] stubble it changed into arrows, for it is written, His sword maketh them as dust, his bow as the driven stubble." Now there was one province which [the emperor had hitherto] not been able to conquer but when they tried some of this earth [against it] they were able to conquer it. Then they took him [Nahum] to the royal treasury and filled his bag with precious stones and pearls and sent him back with great honour. When on his return journey he again spent the night in the same inn he was asked, What did you take [to the king] that they showed you such great honour? He replied, I brought thither what I had taken from here. [The innkeepers] thereupon razed the inn to the ground and took of the earth to the king and they said to him, The earth that was brought to you belonged to us. They tested it and it was not found to be [effective] and the innkeepers were thereupon put to death.
Nahum possessed a very simple yet powerful understanding that everything was of Divine Providence and would work itself out as long as he was faithful, trusting and operated within the parameters of Torah. Despite the possible calamity that could have befallen him, all the events that happened did wind up being for the good, and ultimately saved him and the Jewish people and brought prosperity.
Many times we are faced with mysterious and unfortunate events. Our first response many times is that this is not for the good. However, not being omniscient creatures, how can we know that these things are not for the good? Rather, we must retrain ourselves and equip ourselves with equanimity so as to accept these experiences with calmness of spirit as Nahum did and declare that gam zu l'tovah: this too is for the good.