Prohibition of Riba and other issues
19-1-2003 | IslamWeb
Question:
I sent 5 questions but didn`t receive any answer please answer those my questions 1) why is riba haram 2) I heard that all animals eat meats, we are not allowed to eat it; what about fish that eat each other (I mean meat eat meat; this answer is for a christian person. 3) what about someone make (djanaba) to himself to relax sometime (halal or haram) 4) what about sex with wife without covering our selves but we still in our room anyway. 5) Exactly what is haram in sex way with wife exept anal sex. These questions are veru important to me.Thank you.
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
Al-Fakhr Ar-Raazi 
mentioned the following five reasons for the prohibition of Riba (usury and/or interest)
1- Riba requires taking other people's money for nothing. For example, one who takes two Dirhams in cash or credit for one, he receives one Dirham for nothing. Then, money is badly needed in order to fulfill one's needs and it has great inviolability for the Prophetic Hadeeth that reads: "A person's wealth is as sacred (inviolable) as his blood." Thus, it becomes forbidden to take one's wealth for nothing.
2- Allah, The Exalted, has prohibited Riba since it may lead one to be jobless, i.e. prevents one from working to earn money. In other words, a rich person can get more money through Riba and this makes him earn livelihood easily without any effort that is needed in trade, industry or work in general. So, this practice (i.e. Riba) will deny so many benefits from reaching people, and it is well-known that the public interest depends on trade, industry, and other forms of business.
3- Riba prevents people from giving money as a good loan, which constitutes one of the best favors among people.
4- In general, one who deals with Riba is a rich man and the person who receives such a usurious loan is poor. Thus, the rich become better able to take more money from the poor. In fact, this is illegal from the point of view of mercy, i.e. refused by the Divine Mercy.
5- Riba is strictly forbidden as proved in the Quran. Then, it is not necessary for human beings to recognize the wisdom behind the prohibition. In other words, we are to believe in its prohibition whether or not we know its wisdom.
Without a doubt, all that is mentioned above is proved. We pray to Allah to keep us away from dealing in Riba.
As for eating ravenous fish like shark, there are two opinions:
1- It is forbidden to eat any predatory animal. It is proved in the Sunnah according to the Hadeeth by Muslim and others that it is forbidden to eat any predatory animal that has canine teeth or a bird that has claws.
2- It is lawful to eat ravenous fish since general evidence supports such an opinion.
Allah Says (what means): {Lawful to you is game from the sea and its food as provision for you and the travelers, but forbidden to you is game from the land as long as you are in the state of Ihram. And fear Allah to whom you will be gathered.} [Quran 5:96]
Moreover, the prophetic Hadeeth reads: “Water is from the sea is pure and its dead animals are lawful to eat.” [Ahmad, An-Nassaa’i and Ibn Maajah]
We think that the 2nd opinion is the dominant one.
As regards the answers for your other questions, please refer to Fataawa
Allah Knows best.