Question: where in the bible does it say that being left handed is a sin?
Answer: In Judges 3:15-21, Isreal's second judge after Othniel was Ehud. After Othniel's death, the people of Israel sinned and were defeated by the king of moab, and served him for 18 years (Judges 3:13–14.) Actually no. The bible never mentions left handedness as a sin.