A vow is a tradition that has been passed down since ancient times. It is so old that no one remembers its origin. It is a pledge in which a person in power puts themselves on the line.
One had to know the three vows.
The first pledge requires putting the power at stake. They vow to surrender their own magic to the person they dedicate their vow. If they betrayed that person, they lose their magic forever.
The second pledge is the pledge of the heart at stake. Where not only do they surrender their internal organs but also their flesh, bones, and blood to the person they pledge. Losing their lives.
Being the last pledge, surrendering their soul. This is one of the worst of the three pledges.