Taken From the Fatawaa of our Shaykh, Allaama Mufti of the Kingdom of Saudi Arabia Abdul Azeez bin Abdullaah Bin Baz
Translated by Abbas Abu Yahya [Taken from : binbaz.org.sa via Sahab.net]

Question: If a person is put to trial with a sickness or an evil affliction physically or with his wealth, how does he know that this trial is a test or Anger from Allaah?

Answer: Allaah Azza Wa Jal tests His slaves in prosperity and adversity, in hardship and ease. He sometimes tests them with these things to raise their grade and to enhance the status of those people and to double their good deeds. Like what Allaah did for the Prophets and Messengers – alayhim as-Salat wa Sallam, as well as the righteous people from the worshippers of Allaah.

Like the Prophet – sallAllaahu alayhi wa sallam – said: the most severely of the people to be trialed are the Prophets, then those who are next in grade, then the next.

Sometimes Allaah does this due to the sins and transgression of the people, so that the punishment can be hurried.

Like Allaah Subhanahu said:
<< And whatever of misfortune befalls you, it is because of what your hands have earned. And He pardons much. >>

So, what is general for humans is that they are deficient, and they do not observe all the obligatory duties. Therefore, what afflicts them is due to their sins and shortcomings with regard to Allaah’s commands.

For this reason, if someone from the righteous slaves of Allaah is afflicted with some disease or something similar, then this is from the type of trials for the Prophets and Messengers, raising of their grades and increase of reward, to be an example for others, in having patience and contentment.

So briefly, it could be a test to raise grades and to make the reward greater, like Allaah does for some of the righteous people. It could be expiation for evil deeds, as is mentioned in the saying of Allaah Ta’ala:
<< whosoever works evil, will have the recompense thereof >>

Also the saying of the Prophet – sallAllaahu alayhi wa sallam –: A Muslim is not afflicted with distress, nor sorrow, nor disease nor hardship, nor sadness nor any harm except that Allaah expiates from his sins even by a thorn that pricks him.

The saying of the Prophet – sallAllaahu alayhi wa sallam – whom so ever Allaah intends good for, Allaah compels him with a trial. It could be that this is a punishment which has been hastened due to transgression by the slave and him not having hastened in repenting as is mentioned in the hadeeth of the Messenger – sallAllaahu alayhi wa sallam – that he said: ‘If Allaah intends good for His slave then He hastens his punishment in this world, and if Allaah prescribes evil for His slave, then Allaah holds back his sins until He recompenses them for him on the Day of Judgment.’ [ Narrated by Tirmidhi & he declared it hasan]

All Praise belongs to Allaah, may His peace and blessings be upon our final Prophet Muhammad, his family, his Companions and all those who follow his guidance.