During a discussion which related to an ‘Aalim who refrained from accepting doubtful wealth, Hazrat Moulana Ashraf ‘Ali Thaanwi (rahmatullahi ‘alaih) mentioned:

Nowadays, the required level of taqwa and caution is not seen among people in matters relating to wealth. There are many people who confine piety to their ‘ibaadaat (i.e. virtuous deeds and actions). Many are even punctual on tahajjud, chaasht and ishraaq and in completing their wazeefas. However the inordinate passion and love for wealth within their hearts does not seem to decrease. As a result, they do not exercise the required level of precaution in their business dealings and monetary affairs and continue to consume doubtful wealth. (Malfoozaat-e-Hakeemul Ummat 10/27)

Source: Ihyaauddeen.co.za