Imam Abu Hamid al-Ghazali (may Allah have mercy on him) said,

‘Useful knowledge is that which,

makes you grow in the fear of Allah,

increases you in awareness of your defects,

deepens your knowledge of worship of your Lord Most High,

decreases your desire for this world and increases your desire for the life to come, and

opens your eyes to the defects of your actions so that you can guard against them.’