The old saying tying the knot is something that comes from the hand fasting ceremony and old ancient Celtic practice of medieval era. This binds the couple together in by tying knots of cloth around their hands.
I had the pleasure of doing a ceremony this summer for Alastair & Rebecca in Canmore, Alberta at the Canmore Golf & Curling club.
If you want to se a 360 video of the ceremony you can see it here on You Tube. I set up the camera to take this as a test.