You must redeem the firstborn of a donkey with a lamb; but if you do not redeem it, you are to break its neck. You must redeem all the firstborn of your sons. No one shall appear before Me empty-handed.
Here is a repetition of several appointments made before, especially relating to their solemn feasts. When they had made the calf, they proclaimed a feast in honour of it; now, that they might never do so again, they are here charged with the observance of the feasts which God had instituted.
Commenting on Exodus 34:18-27
And thou shalt observe the feast of weeks,.... The feast of Pentecost, called the feast of weeks, because seven sabbaths or weeks, or fifty days, were to be reckoned from the day in the passover feast, on which the sheaf of the wave offering was brought, Lev 23:15 and which was also called the feast of the first fruits of wheat harvest, to distinguish it...
But the firstling of an ass thou shalt redeem with a lamb: and if thou redeem [him] not, then shalt thou break his neck. All the firstborn of thy sons thou shalt redeem. And none shall appear before me empty. (f) Without offering something.