In historical times, those who are frith-bound were sworn to cause no harm to each other, no matter what argument or disagreement there was between them. Typically this was between those related by blood and marriage, but often extended to close neighbors. It meant they are in your “inner yard” which is generally considered the closest two to four homes in your village.
This was a reciprocal agreement, and fostered peace within the community and provided a sense of security.
To violate the frith bond was a serious crime and would, at a minimum, bring exile to the frith-breaker.
Of course, today’s world is very different. Many of us now live in large metro areas and sprawling suburbs. The frith bond is something almost forgotten. In smaller towns, we may see a “neighborhood watch”, which is probably the closest thing to being “frith-like”. However, there’s no oath, no actual commitment or penalty for not looking out for your neighbor.
The frith bond isn’t something people in today’s world broadly value, or is even a concept of which they’re aware. That being said, there’s no reason it can’t be. You can commit this to your close family and friends and they can offer the same to you. It would simply be an agreement, a spoken bond. It might look something like this:
“We mutually agree to avoid causing each other physical, emotional, and mental harm; and to avoid negatively affecting each other’s honor, worth, and luck.”
In modern times, there’s no need for this to be restricted to only your close family and neighbors. It could be between any people, at any distance, as long as it’s not done lightly and it’s given with all honesty and intent to never break that bond.