Hi @Alex70. The reasoning behind the formulation of the Pātimokkha rules can be found in the Vinaya. (The link is to the Monastic Rules of the Theravāda school but there are others). Have a look at the vibhaṅgas (explanations) for the origin stories of the rules. Monks and Nun’s each have their own vibhaṅgas.
If you’re super interested, Volume 1 of The Buddhist Monastic Code, translated and explained by Ṭhānissaro Bhikkhu, covers the material in great detail.
I’m not familiar with Bhikkhu Bodhi’s work regarding the Pātimokkha rules but, as far as I know, Ṭhānissaro Bhikkhu’s two volumes are the definitive guide for monastics and lay people.
I hope that helps.