I don't know if I believe that additional strength can also grow from our existing strength, but I completely understand the potential for growth from weakness.
At least potentially.
Without effort on our part, beginning with recognizing what our weaknesses are, nothing will change.
"Analyzing what you haven't got as well as what you have is a necessary ingredient of a career."
Orison Swett Marden Early 20th century writer, medical doctor, author
In today's speak, a personal SWOT (strength, weaknesses, opportunities, threats) analysis; taking stock of the assets and lack thereof that you bring to the game.
SWOT is typically associated with business rather than the individuals who work in them, but why wouldn't you want to know this about yourself as well?