首楞嚴義疏注經 4.113

4.113

情想不常，剎那變易，或先胎而後卵，先濕而後化，所有受報隨業善惡，故云逐其飛沈。捨身受身無能斷絕，故云眾生相續。

Emotion and thought are not constant, but change from moment to moment: perhaps first womb-born and later egg-born, or first moisture-born and later transformation-born. All retribution undergone follows whether karma is wholesome or unwholesome; hence it says "follow their soaring or sinking." Renouncing bodies and receiving bodies without ever being severed; hence it says "sentient beings continue in succession."