John Calvin Commentary Genesis 34:24

"And unto Hamor and unto Shechem his son hearkened all that went out of the gate of his city; and every male was circumcised, all that went out of the gate of his city." — Genesis 34:24 (ASV)

And unto Hamor and unto Shechem his son hearkened, etc. Apparently, this consent may be ascribed to modesty and humanity; for, by readily obeying their princes and kindly admitting the strangers to an equality of rights in the city, they show themselves, in both respects, modest and humane. But if we reflect on the true significance of circumcision, it will easily appear that they were too much devoted to their own selfish interests.

They knew that, by a new sacrament, they would be committed to a different worship of God. They had not yet been taught that the ablutions and sacrifices, to which they had been accustomed all their lives, were unprofitable trifles. Therefore, to change their religion so carelessly betrays, on their part, a gross contempt of God; for those who seriously worship God never so suddenly cast aside their superstitions unless they are convinced by sound doctrine and arguments.

But the Shechemites, blinded by an evil conscience and by the hope of gain, turn, like men half-brutalized, to an unknown God. Search the isles, (says the Prophet) is there any nation which deserts its gods, who yet are not gods? Yet this was done at Shechem, when no defect had been shown to exist in the received superstitions. Therefore, no one should wonder that a sad result followed this levity of mind.

Nevertheless, Simeon and Levi were not, on that account, excusable for indulging their own cruelty. Indeed, their impiety appears the more detestable because they not only impetuously rush upon men but, in a sense, trample upon the sacred covenant of God, of which alone they make their boast. Certainly, if they had no compassion for the men themselves, yet reverence for God should have restrained their ferocity, when they reflected on the cause from which the weakness of the Shechemites proceeded.