A part of Iman (Belief) in Allah is the forbearance with what Allah has decreed

Allah the Almighty said:

"And whosoever believes in Allah, He guides his heart [to the true Faith with certainty i.e. what has befallen him was already written for him by Allah from the Qadar (Divine Preordainment)] and Allah is the All-Knower of everything." (Surah At-Taghabun: 11)

Alqamah (May Allah be pleased with him) said:

"He (the person referred to in the foregoing verse) is the man who, when struck by an affliction, knows that it is from Allah, accepts it and submits to Him."

Muslim in his Sahih, reported from Abu Hurairah (May Allah be pleased with him) that Allah's Messenger (May the peace and blessing of Allah be upon him) said:

"Two matters among people amount to disbelief: attacking or defaming one's lineage, and bewailing the deceased."

Narrated Ibn Mas'ud (May Allah be pleased with him) that the Prophet (May the peace and blessing of Allah be upon him) said:

"He who slaps the cheeks, tears the clothes and calls to or follows the ways and traditions of the Days of Ignorance, is not from us."

(Reported by Al-Bukhari and Muslim)

Anas (May Allah be pleased with him) narrated that Allah's Messenger (May the peace and blessing of Allah be upon him) said:

"Whenever Allah wills good for His slave, He hastens to punish him in this life; and when He wills evil for His slave, He withholds punishing him for his sins until he comes before Him on the Day of Judgement."

At- Tirmidhi reported that the Prophet (May the peace and blessing of Allah be upon him) said:

"The greatness of the reward is tied to the greatness of the trial. When Allah loves a people, He puts them to the trial. Whoever is acceptant of it will have Allah's acceptance and whoever is displeased and unacceptant with it will gain Allah's displeasure."

Important issues

1) Explanation of the verse in Surah At-Taghabun (64:11).

2) This (i.e. acceptance to Allah's Decree) is part of proper Faith (Iman) in Allah.

3) Disparaging lineage.

4) Intensity of punishment promised to those who slap the cheeks in anguish and tear the clothes and call to the ways of the Days of Ignorance.

5) The sign that Allah wants good for His slave.

6) The sign that Allah wants bad for him.

7) The sign of love of Allah for His worshipper.

8) Forbiddance of being displeased and unacceptant (of Allah's Decree).

9) The merit and reward of being acceptant of tests and trials.