Another important historical factor is the fact that this already very simple religion was further simplified and purified by the early philosophers of ancient China. Our first great philosopher was a founder of naturalism and our second great philosopher was an agnostic.
A vow is a purely religious act which cannot be taken in a fit of passion. It can be taken only with a mind purified and composed and with God as witness.
The more we come out and do good to others the more our hearts will be purified and God will be in them.