For folklore:
Honor the source by understanding where a story comes from before retelling it.
For magick:
Honor the source by understanding the purpose of a practice before adopting it.
For creativity:
Honor the source by creating your own work instead of copying someone else's.
For collaboration:
Honor the source by understanding what the other person is actually trying to accomplish.
And perhaps most importantly:
For people:
Honor the source by seeing who they actually are instead of who you assume them to be.
The source isn't always a book.
Sometimes the source is your own experience.
Your own intuition.
Your own observations.
Your own practice.