Mahāpadānasutta

Suttapiṭaka · Dīghanikāya · Mahāvagga · Vol. 10 · Section 25

[25] Bhikkhus, this is the natural order (dhammatā): when the Bodhisatta emerges from his mother's womb, two streams of water appear from the sky—one cool, one warm—with which they perform the water-rite for the Bodhisatta and his mother. This is the natural order in this case.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.