Arcana Coelestia #4505
4505. 'Their flocks, and their herds' means that they destroyed rational good and natural good. This is clear from the meaning of 'flocks' as rational good, and from the meaning of 'herds' as natural good, dealt with in 2566.
Numbers 3:12-13
12
"Behold, I have taken the Levites from among the children of Israel instead of all the firstborn who open the womb among the children of Israel; and the Levites shall be mine:
13
for all the firstborn are mine. On the day that I struck down all the firstborn in the land of Egypt I made holy to me all the firstborn in Israel, both man and animal. They shall be mine. I am Yahweh."