This is such a simple concept that it is a wonder that it is so often ignored. The principle of the path is that you will reach the destinations along the path as long as you are moving forward.
Say you are in college and you want to be a nurse. You are taking biology classes. You've lined up courses with your advisor's help and will graduate in two years. Classes and labs are situated along the path. Fraternity parties and skipping class to go to the mall are not.
That's easy enough to understand.
All paths are not equal. Your path to becoming a nurse might look different than someone else's. You got a scholarship so your path is straighter than Girl Friend A who is working in a nursing home parttime. And your path and Girl Friend A's path actually reaches the destination. But Girl Friend B says she wants to go to nursing school, but she is waitressing in a bar and going to beautition school because she wants to be able to do her own nails.
You got the picture. The principle of the path is that you will end up where the path is leading. Don't fool yourself by thinking you are on the right path when you see the signs that clearly indicate the path leads somewhere else. Be aware.