What is the difference between wages and a salary?

The Shaykh : I feel very strongly that people do not distinguish between what is called wages and what is called a salary or compensation. This distinction is very fundamental because the results differ radically between taking wages for worship and taking compensation or a reward or the like. Some people may imagine that the matter is formal; what is the difference whether you call it wages or a reward or a fee or compensation or a salary or the like? No, the difference is great and very great, like the difference between one who goes out as a mujahid in the cause of Allah, seeking martyrdom in the cause of Allah, and another who goes out to jihad but hopes for material gain.