Imaam Ibn al-Qayyim – may Allah have mercy upon him – said in his famous book al-Waabil as-Sayyib min Kalaam at-Tayyib
…So if the slave [of Allah] has the right patience that is required of him, then the trials that afflict him will intruth be turned into blessings, and the misfortune will be turned into fortune and that which he disliked will be replaced with something he loves and cherishes.
For verily Allah the Most High, does not test him in order to destroy him, rather He only tests him [with hardship] in order to see his patience and status as a slave. Because Allah has the right to be worshipped at times of hardship aswell as in times of ease, and it is upon the slave [of Allah] to worship his Lord both in times of difficulty and ease, but most of the creation only give Allah His right of worship when it comes to the things they like.
But in reality, this is where the slaves of Allah surpass eachother [i.e worshipping Allah at times of hardship] and it is because of this they are higher in status infront of Allah.
[For an example] Making wudhu with cold water under the intense heat is without a doubt worship, and getting intimate with ones beautiful wife which one loves dearly is similarly worship even spending wealth upon her, his offspring and himself is worship.
[But contrary to this] Making Wudhu with cold water in the intense cold is worship and leaving off sin which the nafs so badly craves for, even though no human being might see you, is worship. And spending from your wealth at times of hardship is worship.
But what a difference!
Taken from: http://khaldun.wordpress.com/