That feels like a bit of a deviation.
I've read 4 or 5 translations, and don't remember similar phrasing.
There's the MIT copy for comparison:
"He who knows other men is discerning; he who knows himself is intelligent. He who overcomes others is strong; he who overcomes himself is mighty. He who is satisfied with his lot is rich; he who goes on acting with energy has a (firm) will."