"I am the vine; you are the branches." (John 15:5a)
In ancient Israel, many grape vines were grown directly on the ground, not on trellises or raised on stakes, as we are used to seeing.
After all, in that part of the world, wood is a somewhat rare commodity, and it would not be wasted on building risers for plants.
Instead, many vines grew directly on the ground. One of the jobs of the vineyard keeper was to make sure the branches did their job: get their sustenance from the main vine and spend their energy producing fruit.
When the vineyard keeper saw those branches developing roots of their own, he would cut them off and put rocks under the exposed part of the branch while it healed. That way, it would not be tempted to develop those roots again that took it away from its main job.
It likely was a painful experience for the branch. Sort of like in life, when our wonderful Master prunes us where we are putting down roots of self-sufficiency that keep us from relying totally on our True Vine.
