We are all tested in various ways by Allah (S.W.T.) in this world. In the Qur’an, in Surah Baqarah (2: 155), Allah States unequivocally that He will test us:
Be sure we shall test you with something of fear and hunger, some loss in goods or lives or the fruits (of your toil), but give glad tidings to those who patiently persevere,
In Surah Muhammad (47: 31) , Allah reiterates that we will be tested:
And We shall try you until We test those among you who strive their utmost and persevere in patience; and We shall try your reported (mettle).
At work, we are sometimes denied a promotion, treated unfairly, or even fired. At home, our children may be a test for us especially in this world of violence, drugs, illicit sex and video games. Some of us may go through a divorce. Others may find that they have an illness that is very challenging. Dear members of our family or friends may die. Often, it is very trying on us, and many of us fall into despair. It is important during these times not to lose hope, but rather to exercise sabr or patience. As Allah (S.W.T.) Himself says in the Qur’an (Surah Baqarah, 2: 286)
On no soul does Allah Place a burden greater than it can bear. It gets every good that it earns, and it suffers every ill that it earns. (Pray 
“Our Lord! Condemn us not if we forget or fall into error; our Lord! Lay not on us a burden Like that which You did lay on those before us; Our Lord! Lay not on us a burden greater than we have strength to bear. Blot out our sins, and grant us forgiveness. Have mercy on us. You are our Protector; Help us against those who stand against faith.”
What is sabr or patience?
1. From the Seerah of the Prophet (s):
‘Ata ibn Rabah related that he heard Ibn ‘Abbas say: “Shall I show you a woman of Paradise?”I said: “Yes, indeed.” He said: “A black woman came to the Prophet, peace be upon him, and said: ‘I suffer from epileptic fits, and because of these, (at times) my body becomes uncovered. Would you invoke Allah, the Exalted One, to cure me of this disease? ‘ The Prophet, peace be upon him, said: ‘If you wish, you can be patient and you will attain Paradise (for this suffering). But if you prefer, I will pray to Allah, the Exalted, to cure you of it?’ The woman said: ‘I will be patient,’ then added: ‘I become uncovered (when I have fits), so invoke Allah for me that I do not become uncovered. ‘ So the Prophet, peace be upon him, prayed for her.” [Source: Fiqh-us-Sunnah, volume 4, #1a]
2. Story of ‘Urwah Ibn Al Zubair
‘Urwah Ibn Al Zubair had an operation, and the doctor amputated his leg. One friend came to visit him. ‘Urwah thought that the fried came to pacify him for the loss of his leg. So ‘Urwah told the visitor: If you came to give me condolence for the loss of my leg, I already submitted to Allah with patience to reward me for its loss. The guest told him, I came to inform you that your son fell down in a stable, and the animals stepped over him, and he died one hour ago. ‘Urwah said: O Allah! You took one child, and left me many…You took one organ from my body, and left me many organs…O Allah! You tested me with my body, and you were kind to leave me with good health. You tested me with the loss of my son, but you were kind in leaving me the rest of my children.
If one is patient, and is among the ones described in the following manner in the Qur’an (Baqarah, 2: 256)
Who say, when afflicted with calamity: “To Allah We belong, and to Him is our return”:-
Then here are the rewards Allah will give that person (2:157):
Rewards of Patience
1. Blessings from Allah. The patient person is blessed by Allah (S.W.T.)
2. Mercy of Allah. When Allah (S.W.T.) gives someone His Mercy, He will let him enter paradise with His Mercy.
3. Guidance of Allah. A patient person will be guided by Allah (S.W.T.) in this world until he meets Him on the Day of Judgment.
Referring to those who are tested and endure with sabr or patience (2:155-156, see above), all of the above three rewards are mentioned by Allah Himself in the Qur’an in Surah Baqarah (2: 157):
“They are those on whom (Descend) blessings from Allah, and Mercy, and they are the ones that receive guidance.”
In Surah Hud (11:11), Allah (S.W.T.) again promises to reward those who are patient in adversity:
Not so do those who show patience and constancy, and work righteousness; for them is forgiveness (of sins) and a great reward.
Patience during Illness
Source: Fiqh-Us-Sunnah, volume 4, #1a
Anyone suffering from an illness should remain patient, for there is no reward better or more enriching than that reserved for those who endure in patience.
Suhaib ibn Sinan narrated that the Prophet (s) said: “How remarkable is the case of the believer! There is good for him in everything, but this is not the case for anyone except for the believer. When the believer receives any good, he is thankful to Allah, and gets a reward. And when some misfortune befalls him, he endures it patiently, for which he is (also)
rewarded.”
Anas narrates: “I heard the Prophet (s) saying: ‘Allah says: “When I afflict a servant of mine with respect to his two most beloved things (meaning his eyes), and he endures it patiently, I grant him paradise in return‘.”
Taken from http://makkah.wordpress.com
Then here are the rewards Allah will give that person (2:157):
Not so do those who show patience and constancy, and work righteousness; for them is forgiveness (of sins) and a great reward.
Source: Fiqh-Us-Sunnah, volume 4, #1a
rewarded.”