John Calvin Commentary Exodus 32:5

"And when Aaron saw [this], he built an altar before it; and Aaron made proclamation, and said, To-morrow shall be a feast to Jehovah." — Exodus 32:5 (ASV)

And, when Aaron saw it, he built an altar before it. When he sees the people so infuriated that he despairs of being able to resist their conspiracy, in treacherous cowardice he yields to compliance.

And this end awaits all those who do not dare sincerely and firmly to maintain what is right, but who bargain, as it were, and descend to compromises; for, after they have wavered for a while,³³² they eventually succumb altogether, so that they stop at nothing, however unworthy and disgraceful.

He seems, indeed, by his proclamation to uplift their minds to the worship of the true God; but, when he is violating the law just given, it is a wretched pretext to shield their offensive and degenerate worship under God’s sacred name.

³³² Addition in Fr., “Et nage entre deux eaux;” and swam between two waters.., “Et nage entre deux eaux;” and swam between two waters.