Where has riba been defined?
No hadith (even if it is zaeef) says that where rate of interest has been fixed or where your efforts are not involved, it becomes Riba. How do you reach that conclusion? Can you please direct me towards any such hadith?
The understanding of riba is not based on hadith. The Quran also doesn’t define riba. However, if we read the Quran carefully, we can infer the definition of riba from it. Riba was not clearly defined because there was no need for it. It was a word whose meanings were known to everyone. You don’t need to define a man, or a woman, or a father, or a mother, because all these words have clearly meanings; likewise was the case with riba. The Quran is not a book of definitions. The word riba was used in the same sense as interest in English and Sud in Urdu.