Avoiding doubtful sources of earning
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنْ دَاوُدَ بْنِ أَبِي هِنْدٍ، عَنْ سَعِيدِ بْنِ أَبِي خَيْرَةَ، عَنِ الْحَسَنِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " يَأْتِي عَلَى النَّاسِ زَمَانٌ يَأْكُلُونَ الرِّبَا فَمَنْ لَمْ يَأْكُلْهُ أَصَابَهُ مِنْ غُبَارِهِ " .
It was narrated that Abu Hurairah said: "The Messenger of Allah (ﷺ) said: "There will come a time when there will be no one left who does not consume Riba, and whoever does not consume it will nevertheless be affected by residue." (Sahih )