1. In the heart, as if he is angry with his Lord, and so he rails against what Allāh has ordained for him, and this is forbidden and could even lead to disbelief. Allāh, the Most High, says:
“And among mankind is he who worships Allah as it were upon the edge (i.e. in doubt): if good befalls him, he is content therewith; but if a trial befalls him he turns back on his face (i.e. reverts to disbelief after embracing Islam). He loses both this world and the Hereafter.” (Al-Hajj 22:11)
2. That it is spoken, such as invoking woe, destruction and the like and this is forbidden.
3. That it is physical, such as striking the cheeks, tearing the clothes and pulling out the hair and the like, and all of this is forbidden, because it negates the patience which is required.
The Second Level: Patience and this is as the poet says:
Patience is like its name, its taste is bitter,
But the end result is of it are sweeter than honey.
So, he considers this burden heavy, yet he bears it, even though he hates that it should occur, and his faith protects him from discontent. So, its occurring or not occurring are not the same to him. This is an obligation, because Allāh, the Most High has commanded him to be patient, saying:
“and be patient. Surely, Allah is with those who are As-Sabirun (the patient).” (Al-Anfal 8:46)
The Third Level: Acceptance: That a person accepts misfortune, so that its presence or absence are the same to him. Its presence is not hard on him, and he does not bear a heavy burden due to it, and this is highly preferred, although not obligatory, according to the most authoritative opinion. The difference between it and the last level is clear, because the presence of misfortune and its absence are the same in the acceptance of this person, whereas in the level before it, misfortune is difficult for him, yet he bears it.
The Fourth Level: Gratitude, and this is the highest level: It is by him thanking Allah for the misfortune which has befallen him, because he knows that this misfortune is a cause of his sins being remitted and and it might also be a cause of his reward being increased. The Prophet salAllahu alayhi wasallam said:
“There is no misfortune that afflicts a Muslim except that Allah remits a sin from him because of it, even the prick he receives from a thorn.” (Reported by Al-Bukhari and Muslim)