Kathavatthu 4.7.8.3

4.7.8.3

yena bodhisattassa udakakiccaṃ karonti mātu ca, evamevaṃ cakkavattisattassa jāyamānassa dve udakassa dhārā antalikkhā pātubhavanti—

wherewith they perform the water service for the bodhisatta and his mother, so too when a wheel-turning being is being born, do two streams of water appear from the sky—