The phrase "guiding force" refers to something or someone that leads or directs others in a particular direction or towards a specific goal. It is like a compass or a mentor that provides guidance and help to make decisions or take actions.
People often let prices be the only guiding force in buying life insurance but choosing the right product for your personal needs. (lifequote.com)
They are willing to discuss things and reason with their children, and act as guiding forces for their children to make decisions. (powerfulmothering.com)
Common sense should be guiding force of Internet security for schools. (edutopia.org)