John Calvin Reformed @genevareformer

Here the Prophet, anticipating an objection, shows that the Israelites deceived themselves, for they believed that God was pacified by their sacrifices: he declares all these to be useless; not only, as I think, because they themselves were impure; but because all their sacrifices were mere profanations.

Matthew Henry Presbyterian @wholebiblehenry

The scope of these verses is to show how little God valued their shows of devotion, nay, how much he detested them, while they went on in their sins. Observe, I. How unpleasing, nay, how displeasing, their hypocritical services were to God. They had their feast-days at Bethel, in imitation of those at Jerusalem, in which they pretended to rejoice before God.

Commenting on Amos 5:21-27

John Gill Reformed Baptist @doctorgill

I hate, I despise your feast days,.... Kimchi thinks this is said, and what follows, with respect to the kingdom of the house of Judah, which kept the feast the Lord commanded; but it is not necessary so to understand it; for doubtless the ten tribes imitated the worship at Jerusalem, and kept the feasts as the Jews did there, in the observance of which...