Give up riba and doubtful things .

This hadith is about avoiding riba or usury which is a type of loan where the borrower pays back more than what they borrowed. The last verse revealed in the Quran was about this topic but unfortunately Prophet Muhammad passed away before he could explain it to his companions. Therefore, 'Umar bin al-Khattab advised them to give up riba as well as anything that is doubtful or uncertain. This hadith teaches us to stay away from any kind of transaction that involves taking advantage of someone else's financial situation or taking something without giving something in return. It also encourages people to be careful when dealing with money matters and not take part in any activities that are uncertain or unclear.