A living community changes over time. From early family units, to larger tribal groups (clans) there is a common core of customs which develop. These become the "laws" [spoke or unspoken] that begin to structure the obligations of the folks living within the community, and institute controls [often punishment] that establish authority within this cluster of folks trying to survive. For the Welsh, this was well established by the mid-10th century. This common core became associated with the name of Hywel Dda.
On page 71 it records:
"For the wise say that worldly law does not pursue any person (whether it is to heaven that he goes or to hell) save until he leaves the earth. This is the reason for it: Though there be law between persons and each other on this earth, there is no law between angels and each other, and there is no law between devils and each other, save the will of God."
Hum..."the will of God"...who would have guessed this would be a customary principle in the laws of Hywel Dda, around 942 AD.