Hadith 608
۞
Hadith.3725 - The Commander of the Faithful (as) said:
"Whoever engages in trade without knowledge will fall into usury, and then fall into it again. Therefore, no one should sit in the marketplace except one who understands buying and selling."
3725 - وَ قَالَ أَمِيرُ اَلْمُؤْمِنِينَ عَلَيْهِ اَلسَّلاَمُ : "مَنِ اِتَّجَرَ بِغَيْرِ عِلْمٍ اِرْتَطَمَ فِي اَلرِّبَا ثُمَّ اِرْتَطَمَ فَلاَ يَقْعُدَنَّ فِي اَلسُّوقِ إِلاَّ مَنْ يَعْقِلُ اَلشِّرَاءَ وَ اَلْبَيْعَ".