Worship of Ease vs. Worship of Difficulty
 - Ibn al-Qayyim

"...Indeed, Allah has tasked His slaves with worship in difficult conditions just as He has in conditions of ease. He has tasked them with worship in what they dislike just as He has tasked them with worship in what they love. Most people are given the chance to worship in regards to what they love. However, the true distinguishing factor is when one worships during conditions that he dislikes, as this is what makes a person degrees and degrees above others, and this is what determines his level with Allah.

So, making ablution with cold water in extremely hot weather is worship, and kissing your beautiful wife that you love is worship, and spending money on her, the children, and yourself is worship. This same ablution with cold water in extremely cold weather is also worship, and abandoning a very tempting sin when there is no fear of anyone finding out is also worship, and spending your money in times of poverty is also worship.

However, there is a huge difference between the two sets of worship!

['al-Wabil as-Sayyib'; p. 22-23]