Full Idea
Every coming-to-be is a passing away of something else and every passing-away some other thing's coming-to-be.
Gist of Idea
All comings-to-be are passings-away, and vice versa
Source
Aristotle (Coming-to-be and Passing-away (Gen/Corr) [c.335 BCE], 319a07)
Book Reference
Aristotle: 'The Basic Works of Aristotle', ed/tr. McKeon,Richard [Modern Library Classics 2001], p.483
A Reaction
This seems to be the closest that Aristotle gets to sympathy with the Heraclitus view that all is flux. When a sparrow dies and disappears, I am not at all clear what comes to be, except some ex-sparrow material.