Some smart person put wisdom into a sentence. Ready for you to consume, remember and read later.
This is a catch-phrase that makes it easy to convey a complex meaning in an easy-to-communicate way. It reduces the mental load of remembering, discussing and applying certain useful concepts.
This is a little framework somebody came up with to solve specific types of problems. It's what you learn from coworkers, in trainings to make your life easier. It can be a type of chart, a way of structuring something or a small piece of software.