John Calvin Commentary Matthew 5:11

"Blessed are ye when [men] shall reproach you, and persecute you, and say all manner of evil against you falsely, for my sake." — Matthew 5:11 (ASV)

When they shall cast reproaches on you (Luke 6:22); when men shall hate you, and separate you, and load you with reproaches, and cast out your name as evil. By these words Christ intended to comfort those who believe in him, so that they might not lose courage, even though they see themselves to be detestable in the eyes of the world. For this was no light temptation, to be thrown out of the Church as ungodly and profane.

Christ knew that there is no kind of person more venomous than hypocrites, and foresaw with what furious madness the enemies of the Gospel would attack his small and despised flock. It was therefore his will to furnish them with a sure defense, so that they might not give way, though an immense mass of reproaches was ready to overwhelm them. And so it appears how little reason there is to dread the excommunication of the Pope, when those tyrants banish us from their synagogues because we are unwilling to renounce Christ.