Singleness of purpose is one of the chief essentials for success in life, no matter what may be one’s aim.
John D. Rockefeller
As the famous 19th and early 20th century oil magnate points out here, it is extremely important to be focused. In fact, the term “singleness of purpose” implies something beyond focus; we must first have a sense of purpose and then be laser-focused on that purpose. Since we typically have to deal with many aspects of life, not just our business ventures, I would add to this quote that it is important to be focused on the particular venture or other issue you are working on at a particular moment — give it everything you have. Eliminate unimportant distractions and pursue your objectives with a “singleness of purpose”.