Shaikhul Islaam Ibn Taymiyyah (rahimahullaah) said:
Many of the latter people (i.e. those who came after the Salaf) associated Zuhd with poverty, but Zuhd can be (present) alongside wealth and poverty. Amongst the Prophets and those who were foremost in embracing Eemaan (i.e. the Sahaabah), there were those who were wealthy and Zaahid (i.e. a person of abstinence). [Majmoo 11/28]
Ibraaheem Bin Ad’ham (rahimahullaah) said:
Abstinence from the worldly life is of three types: (a) Obligatory abstinence, (b) the abstinence that is of a superior virtue and (c) the abstinence that is safety. As for obligatory abstinence, it is to abstinence from the unlawful; and the abstinence that is of superior virtue is to abstain from what is lawful (but unnecessary); and the abstinence that is safety is to abstain from the doubtful matters.
[Jaami-ul Uloom Wal-Hikam: page: 310]