The Function of the Precept Body of the Five Precepts

Taking the threefold refuge does not equal receiving the five precepts. In receiving precepts, one obtains the precept essence (receptacle of the precepts), whereas in taking refuge there is no precept essence of the five precepts. The precept essence has the function of preventing the violation of precepts, and there are also precept-guarding deities who protect it, enabling one to prevent wrongdoing and stop evil, to avoid experiencing the karmic retribution of evil deeds even in small measure, and to progress quickly in cultivation. If one violates the precepts right after receiving them, this shows that one did not obtain the precept essence. The reason for not obtaining the precept essence is that one's own karmic offenses have not been purified through repentance; there were obstructions at the time of receiving the precepts. One needs to repent and purify oneself again and then receive the precepts once more, until the precept essence is obtained. 

If the master who confers the precepts upon you has himself violated the precepts and lost the precept essence, then you will not obtain the precept essence by receiving precepts from him. Therefore, to be safe, one may receive the precepts several times. If the precept-conferring master is accomplished in cultivation and virtuous, then the Buddhas, Bodhisattvas, and Dharma-protecting deities will provide good support and protection; at the time of receiving the precepts, the power of blessing will be great and the spiritual response great, and after receiving the precepts one's transformation will be great, with one's progress on the Path advancing relatively quickly.