Three types of Words of the Buddha

There are three types of Words of the Buddha (ka sum [Tib.]), in terms of their medium of transmission (bdag rkyen [Wyl.])sometimes translated as the "three transmitted precepts". They are:

1. The oral teachings (sungwé ka [Tib.]);
2. The teachings given through blessings (chinji labpé ka [Tib.]), as when while in meditation the Buddha blessed Avalokiteshvara and Shariputra and the Heart Sutra arose;
3. The repeated teachings (rjes su nangwé ka [Tib.]), at the beginning of which teaching it says, "Thus have I heard" and at the end, "This is how the Buddha spoke".