Synopsis: Whatever our station in life, to each of us are given the same set of tools to make of our lives what we will. Some spend their tools in making themselves one stumbling block after another; others, a stepping stone.
The bag of tools that the poet alludes to is the power of thought. The power of decision.
Whether you are born into a rich or a poor family, whether you are educated or not, you have the power to change your results by using the one resource that is the agency of all change -- thought. You may use it to remember all the bad things that happened so far, crib, and focus on all that's not working in your life, and thus create for yourself poverty, misery and defeat. Or, you may use the same power of thinking to focus on what you want to make happen, and thus create one stepping stone after another on your journey to success.
"Isn't it strange that princes and kings
And clowns that caper in sawdust rings;
And common folks, like you and me,
All are builders for eternity."
"To each is given a book of rules,
A shapeless mass and a bag of tools;
And each must shape ere life has flown,
A stumbling block or a stepping stone."