Question:

What does Ecclesiasates 10:2 tell us? Is there anything wrong with left-handedness?

Answer:

"A wise man's heart is at his right hand, but a fool's heart at his left" (Ecclesiastes 10:2).

Being left-handed is far less common than being right-handed. It is unusual enough that it is mentioned as a feature of some people. You never hear of someone being a right-handed man, but God mentions that Ehud was left-handed (Judges 3:15) because it explains how Ehud snuck a sword into the king's palace. There were also 700 warriors with perfect aim with a sling who all happened to be left-handed (Judges 20:16).

Whichever is your dominant hand, it is stronger and more nimble than the other. Since the majority of the world is right-handed, Solomon wrote his point from that viewpoint. A wise man's heart is in his dominant (right) hand. He makes use of it with dexterity and strength. Thus, the wise man exercises self-control over his emotions while putting those emotions to good use. A fool's heart is in his weaker (left) hand. He has a hard time controlling his emotions, he handles them sloppily and they often run away with him.