Charles Ellicott Commentary Exodus 34:20

"And the firstling of an ass thou shalt redeem with a lamb: and if thou wilt not redeem it, then thou shalt break its neck. All the first-born of thy sons thou shalt redeem. And none shall appear before me empty." — Exodus 34:20 (ASV)

The firstling of an ass. —See Notes 1-3 on Exodus 13:13.