Repentance is key...... We sin knowingly and unknowingly and sometimes the people we wrong are angels in disguise.... Their tears can affect your life and you won't even know it.
Deuteronomy 23:19 “You shall not charge interest to your countrymen: interest on money, food, or anything that may be loaned at interest. Qur'an 2:275 Those who consume interest cannot stand [on the Day of Resurrection] except as one stands who is being beaten by Satan into insanity. That is because they say, "Trade is [just] like interest." But Allah has permitted trade and has forbidden interest.