A wise man's heart, i.e. his understanding or wisdom, is at his right hand; is always present with him, and ready to direct him in all his actions. He manageth all his affairs prudently and piously. He mentions the right hand, because that is the chief and most common instrument of actions, which by most men are done with more strength, and expedition, and orderliness, and comeliness by their right hand than by their left. A fool's heart at his left; his understanding and knowledge serves him only for idle speculation and vain ostentation, but is not at all useful or effectual to govern his affections and actions. He acts preposterously and foolishly, like one without heart, as it follows.
Related Commentaries of Ecclesiastes 10:2
Ecclesiastes 10:2
2 A wise man's heart is at his right hand; but a fool's heart at his left.