Jaiminīya Upaniṣad Brāhmaṇa 3.8

His kinsmen were as if tearful, thinking: "He has undertaken one or the other [perilous contest]."

For in ancient times, when anyone engaged in a theological disputation, they thought: "He has undertaken one or the other [survival or destruction]."
And they treated him as if he were already dead.

The charioteer said to him: "Sir, since you are not on good terms with them, why do you speak thus?"

"Om," he said, "I must go; my teacher considered me easy to guide."

Mounting the chariot, he drove forward.
They looked toward him:

"Whom do you recognise?"
"Sudakṣiṇa."
"Surely he would not come down here!"
"It is he indeed."

Remaining in his shoes, he stood inside the sacrificial altar ground and said: "Well now, householder!"
He would not stand up for him.
He said: "Rise up for me! You are wearing a black antelope skin."
These Kuru-Pañcālas realised that, and said: "Rise up indeed for him!"

The younger brother said to him: "Sir, rise up for the udgātṛ."
He rose up for him.

He said: "A person, O householder, is born three times.
First he is born from the father, then from the mother, then from the sacrifice.

And three times indeed he dies.
When the father pours him into the womb as semen—
Third khaṇḍa in the second anuvāka.