“If you want to do something good, then do not put it off until tomorrow..”

 ‘Ibn al-Mubaarak narrated that al-Haarith ibn Qays said: 

 

If you want to do something good, then do not put it off until tomorrow; if you are doing something pertaining to the Hereafter, then continue as long as you can; if you are praying and the Shaytaan tells you that you are showing off (by making it long), then make it longer.'

Az-Zuhd by Ibn al-Mubaarak  (p.12)