Transmigration due to karma is taught in the Upaniṣads and in the Abhidharma writings. If a bodhisattva who has practiced the bodhisattva way accepts rebirth as a buddha in a buddha-realm, his links with the beings of this present existence would be severed. Therefore, for the sake of the salvation of living beings, he determines, of himself, that he has to remain in the Sāha world. With the growth of the idea of the Bodhisattva Vow there came the understanding that the power of the vow enabled the bodhisattva to remain outside the force of karmic cause and effect and to select the place of his rebirth himself. This is termed “rebirth by vow” as opposed to “rebirth through karma.”

The new religious movement, with its roots in Buddhist and Indian intellectual history, eventually came to be known by the subjective appellation Mahayana, meaning the great, or superior, vehicle.