It is an expression used to describe someone who fails to accept responsibility. They blame something or someone else instead of admitting that they are at fault
the origin of this is to be found in the 13th Century, possibly French. 'A bad workman will never find a good tool' In 1640 the quotation was 'never had ill workmen good tools'
like a child did not completed his test because he did not prepared for it. When it is the time to submit the papers he will say that my pens ink was finished so i could not complete it.