It is worthwhile to pay attention to the fact that one core teaching which appears in both the Chang Ahan of the Northern tradition and the Dighanikaya of the Southern tradition is the formula of the threefold training. The sequence of the relevant texts differs but both contain long identical passages which deal in formal fashion with the threefold training. They appear for the first time in the twentieth sutra of the Chang Ahan and the second one of the Dighanikaya. In both cases, the following sutras contain corresponding passages, the only difference being that they are indicated by way of abbreviation. Both the Chang Ahan of the Northern tradition and the Dighanikaya of the Southern tradition are comprised of thirty-six independent texts in twelve of which the formula of the threefold training appears. It should be noted that no other formula of similar importance can be found in the Chang Ahan. This indicates very strongly that this is the core teaching of the scripture. It is not simply, as later tradition wants to have it, that“the Chang Ahan is there to refute the non-Buddhists”or is“blessing and edification.”The present paper furthermore adduces the Sravakabhumi in order to explain the main meaning of the formula of the three trainings, and finally compares the relevant text of the Chang Ahan and Dighanikaya.