Al-Imaam Ahmad bin Hanbal said: Az-Zuhd is of three types:
The first: Abandoning that which is haraam [forbidden]-– and it is the zuhd of the general folk.
The second: Abandoning the excesses of that which is halaal [lawful ] – and it is the zuhd of the people of distinction.
The third: Abandoning that which busies one from Allaah – and it is the zuhd of the acquainted ones.
By: Imaam Ahmad bin Hanbal