The supreme truth, Shariputra, is a synonym for the quintessence of beings. The quintessence of beings, Shariputra, is a synonym for the Tathagatagarbha. The Tathagatagarbha, Shariputra, is a synonym for the Dharmakaya.
This same Dharmakaya the Tathagata has spoken of, Shariputra, possesses qualities inseparable, and wisdom and attributes indivisible —that is, inseparable from qualities definitive of a Tathagata, more numerous than the sands of the Ganges river.
—Buddha Shakyamuni, Discourse on the Absence of Increase and Decrease