Final answer:
Franklin is saying that it is important to have a purpose or be productive.
Step-by-step explanation:
If idle means worthless, then Franklin is saying that it is important to have a purpose or be productive. In the quote provided by Dwight D. Eisenhower, he mentions quitting work at 7:30 p.m. and not having the heart to go on tonight. This implies that Franklin believed in working diligently and not being idle to achieve success. By being productive and purposeful, one can accomplish their goals and contribute to society.