The sūtra-mātṛkā (sūtra matrix, 契經, 摩呾理迦 or 本母)

The collection certainly contains the most essential teachings of Buddhist thought.

However, to say that the collection is the earliest section in SA/SN is not just based on the most essential teachings. It is mainly based on the three-anga structure (sutra, geya, vyakarana angas) of SA/SN, and the sutra-anga was the earliest of the three angas, according to Yin Shun.

This historical view on the formation of EBTs is completely different from the Pali tradition, which the nine-fold aṅga made up the entire Nikāyas of the Sutta-piṭaka was established at once in the first council.

Cf.:

  1. The Samyutta Nikaya as the earliest of the EBTs - Discussion - Discuss & Discover

  2. The Samyutta Nikaya as the earliest of the EBTs - Discussion - Discuss & Discover

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