The Buddha's enlightenment and turning of the Dharma wheel were both manifestations and explications of the "Dharma". Hence,in the earlist days of the sangha, the guiding principle for the maintenance of monastic standards was the "Dharma". The Buddha's own purity in word and deed served as the highest standard for members of the sangha. In the regulation of individual and community life,a set of standards was necessary; these standards were derived from the "study of the Dharma". Although monks who transgressed the principles of this study could be criticized and warned,there was at first no powerful mechanism for punishment and reform. During this period of some twelve years -- that is, the period of the foundation of the monastic order -- bhiksus were exceptionally committed and sincere so that there were no transgressions of the spirit of the Dharma. Twelve years later,however,when an offense occusrred,the Buddha implemented the Vinaya in order to restrain the community in word and deed.
Because of the need for "objective" standards for the determination of the severity of a given transgression,in the bodhisattva precepts there are many passages based on "motivational transgressions" which could only have served as encouragement on a personal moral level.
Just before the Buddha passed into Nirvana, he exhorted his disciples to "take the precepts as their master." This is not to say that the "Vinaya is supreme." Rather,it is an encouragement to the assembly to establish the concept of "law" in the hope that the sangha would thereby maintain its purity,allowing the correct Dharma to be widely propagated.
"If the regulation penalize those who have committed no faults, sentient beings will not accept them." Therefore,in general,the regulations were governed by the principle of "establishing rules as transgressions occur." Nevertheless, later on the principle of "establishing rules as transgressions occur" was carried to extremes, giving rise to the tendency of all -- inclusiveness. In this way some regulations -- created for the exigencies of the moment -- eventually lost their relevance. In fact,some aspects of certain transgressions are purely theoretical divisions, and were not necessarily "established as transgressions occurred." Most legal canons undergo the same process of beginning with the principle of "establishing rules as transgressions occur",but eventually allowing for the categorization and additions of legal specialists.