John Calvin Commentary 2 Thessalonians 2:11

"And for this cause God sendeth them a working of error, that they should believe a lie:" — 2 Thessalonians 2:11 (ASV)

The working of delusion. He means that errors will not merely have a place, but the wicked will be blinded, so that they will rush forward to ruin without consideration. For as God enlightens us inwardly by His Spirit, so that His doctrine may be effective in us, and opens our eyes and hearts so that it may make its way there, so by a righteous judgment He delivers over to a reprobate mind (Romans 1:28) those whom He has appointed to destruction, so that with closed eyes and a senseless mind, they may, as if bewitched, hand themselves over to Satan and his ministers to be deceived.

And surely we have a striking example of this in the Papacy. No words can express how monstrous a sink of errors there is there, how gross and shameful an absurdity of superstitions there is, and what delusions contrary to common sense. No one with even a moderate understanding of sound doctrine can think of such monstrous things without the greatest horror. How, then, could the whole world be lost in astonishment at them, unless people had been struck with blindness by the Lord and turned, as it were, into stumps?