“So long as you are in this world,
be not surprised at the existence of sorrows.
For truly it manifests nothing but what is in keeping
with its character or inevitable nature.”
-Shaykh Ibn ‘Ata’illah

“He has afflicted you from every direction in order to pull you back to the Directionless.”
-Mawlana Rumi

“The world was designed to break your heart…and God is with the broken-hearted.”
-Shaykh Hamza Yusuf

Ahadeeth:
The extent of the reward will be in accordance with the extent of the trial (fitna). If God loves a people, He tries them, and whoever is content will have contentment, and whoever is angry will have anger. (Reported by al-Tirmidhi, 2320; Sahih al-Jami, 2210).

There is nothing that befalls a believer, not even a thorn that pricks him, but God will record one good deed for him and will remove one bad deed from him. (Muslim)

On the Day of Resurrection, when people who had suffered affliction are given their reward, those who were healthy will wish their skins had been cut to pieces with scissors when they were in the world (when they see the immense rewards for the afflictions they suffered). (Tirmidhi)

Trials will continue to befall the believing man and woman, with regard to themselves, their children and their wealth, until they meet God with no sin on them. (Tirmidhi)

If you put your trust completely in God, He will arrange for your sustenance in the same way as He provides for the birds. They go out in the morning with their stomachs empty and return filled in the evening. (Tirmidhi)

The greatest reward comes with the greatest trial. When God loves a people He tests them. Whoever accepts that wins His pleasure but whoever is discontent with that earns His wrath. (Tirmidhi)

Wisdom from Past Scholars:

Mawlana Rumi said:
“Whoever is more awake has greater pain, whoever is more aware has a yellower face.” (Mathnawi I 629)
“Every heartache and suffering that enters your body and heart pulls you by the ear to the promised abode.” (Diwan 35486-87)
“My heart is so small, it’s almost invisible.  How can You place such great sorrows in it?  “Look,” He answered, “Your eyes are even smaller, yet they behold the world.”

Shams Tabrizi said:

“Whatever happens in your life, no matter how troubling things might seem, do not enter the neighborhood of despair. Even when all doors remained closed, God will open up a new path only for you.  Be thankful! It is easy to be thankful when all is well.  A Sufi is thankful not only for what he has been given but also for all that he has been denied.”
“Patience does not mean to passively endure.  It means to be farsighted enough to trust the end result of a process. What does patience mean?  It means to look at the thorn and see the rose, to look at the night and see the dawn.  Impatience means to be shortsighted as to not be able to see the outcome.  The lovers of God never run out of patience, for they know that time is needed for the crescent moon to become full.”

Al-Hasan al-Basri said:
“Do not resent the calamities that come and the disasters that occur, for perhaps in something that you dislike will be your salvation, and perhaps in something that you prefer will be your doom.”

Ibn Taymiyah said:
“A calamity that makes you turn to God is better for you than a blessing which makes you forget the remembrance of God.”

Imam Ghazali said:
“In the intricate paths of life when difficulties and hardships confront a man, and the darkness of difficulty and suffering becomes long, it is patience only that acts like a light for a Muslim, that keeps him safe from wandering here and there, and saves him from the muddy marsh of disappointment, desperation and frustration.”

Al Jami’ (The Gatherer) said:
“Your preoccupation with this world: eating, drinking, seeking more and more to eat, to have, to enjoy: your slavery at the hands of your flesh and your ego have made you inattentive to everything else. Only when the bird of the soul flies free from the cage of the flesh will this dream evaporate, and you will find yourself alone with your deeds. Then you will see that single companion whom you hug and press to your chest. Is it something warm and friendly, or is it full of snakes and scorpions and poisonous thorns? Then you will know what you presumed to be good was Hell, and what you thought was suffering was Paradise.”

Shurayh Al-Qaadi said:
“If I am afflicted with a calamity, I praise God for it four times: I praise Him because it wasn’t worse than it was, I praise Him when He gives me the patience to bear it, I praise Him for enabling me to say al-istirjaa (‘To God we belong and to him we will return’) in hope of a great reward, and I praise Him for not making it a calamity in my religion.”
-Adh-Dhahabi, Siyar Alaam An-Nubalaa’

Imam Sha’rani said (paraphrased by me):
Afflictions can be three things: a purification, an elevation in status with Allah, and a punishment. If you are pleased with the affliction, it is an elevation for you in rank. If you are displeased, it is a punishment for you.

On Du’as (Invocations to God):
God’s Messenger said, “The invocation of anyone of you is granted (by God) if he does not show impatience (by saying, ‘I invoked God but my request has not been granted.’) (Book #75, Hadith #352)

According to Shaykh Hussain Abdul Sattar, when a person witnesses the rewards and the answers to his earthly du’as in the afterlife , he/she will say, “I wish that none of my du’as were answered on earth!”