As I discuss in this answer, each of the four Vedas consists of four portions: Samhitas, the core part of the Vedas consisting of verses heard from the gods; Brahmanas, which provide instructions on the proper performance of important rituals; Aranyakas, which provide a guide to rituals meant for forest-dwellers and hermits; and Upanishads, which consist of conversations between teachers and students which clarify the philosophical message of the Vedas. But as I discuss in this answer, the Shukla Yajur Veda is organized differently. In particular, one of its Upanishads, the Brihadaranyaka Upanishad, is actually the last part of its Brahmana, the Shatapatha Brahamna.
Now the Shukla Yajur Veda is associated with the sage Yajnavalkya, and the last chapter of the Brihadaranyaka Upanishad (i.e. the last chapter of the Shatapatha Brahmana) tells the disciplic succession by which Yajnavalkya got the knowledge embodied in the text:
- Yâgñavalkya [learned it] from Uddâlaka,
- Uddâlaka from Aruna,
- Aruna from Upavesi,
- Upavesi from Kusri,
- Kusri from Vâgasravas,
- Vâgasravas from Gihvâvat Vâdhyoga,
- Gihvâvat Vâdhyoga from Asita Vârshagana,
- Asita Vârshagana from Harita Kasyapa,
- Harita Kasyapa from Silpa Kasyapa,
- Silpa Kasyapa from Kasyapa Naidhruvi,
- Kasyapa Naidhruvi from Vâk,
- Vâk from Ambhinî,
- Ambhinî from Âditya, the Sun.
As you can see, it eventually goes back to the sage Kashyapa who learned it from Vak goddess of speech, more commonly known as Saraswati. But my question is, who is this "Ambhini" figure, who apparently learned the knowledge from Surya the sun god and taught it to Saraswati? Is Ambhini a goddess?
I found one possible clue. As you can see in the Rig Veda Anukramani in my answer here, Saraswati is the seer of one of the hymns in the Rig Veda, specifically Book 10 Hymn 125. Her name is listed there as "Vak Ambhrina" (which would mean daughter of Ambhrini or Ambhrina). Could this last name "Ambhrina" have some connection to "Ambhini"?
Are there any scriptures that describe Ambhini?
EDIT: I found a reference to Vak Ambhrina in this excerpt from the Baudhayana Shrauta Sutras:
Vak, daughter of Ambhrina, desired, "May I attain immeasurable glory." She perceived this sacrifice, she fetched, she performed it. Thereby she attained immeasurable glory.