Calvin was surprised by a larger audience than usual on a weekday that fell on December 25, 1550/51. I guess he hadn't gotten the worship/evangelism committee's memo about appropriating Advent season from the papists.
"Now, I see here today more people that I am accustomed to having at the sermon. Why is that? It is Christmas day. And who told you this? You poor beasts. That is a fitting euphemism for all of you who have come here today to honor Noel. Did you think you would be honoring God? Consider what sort of obedience to God your coming displays. In your mind, you are celebrating a holiday for God, or turning today into one but so much for that. In truth, as you have often been admonished, it is good to set aside one day out of the year in which we are reminded of all the good that has occurred because of Christ’s birth in the world, and in which we hear the story of his birth retold, which will be done Sunday. But if you think that Jesus Christ was born today, you are as crazed as wild beasts. For when you elevate one day alone for the purpose of worshipping God, you have just turned it into an idol. True, you insist that you have done so for the honor of God, but it is more for the honor of the devil.
Let us consider what our Lord has to say on the matter. Was it not Saul’s intention to worship God when he spared Agag, the king of the Amalekites, along with the best spoils and cattle? He says as much: ‘I want to worship God.’ Saul’s tongue was full of devotion and good intention. But what was the response he received? ‘You soothsayer! You heretic! You apostate! You claim to be honoring God, but God rejects you and disavows all that you have done.’ Consequently, the same is true of our actions. For no day is superior to another. It matters not whether we recall our Lord’s nativity on a Wednesday, Thursday, or some other day. But when we insist on establishing a service of worship based on our whim, we blaspheme God, and create an idol, though we have done it all in the name of God.73 And when you worship God in the idleness of a holiday spirit, that is a heavy sin to bear, and one which attracts others about it, until we reach the height of iniquity. Therefore, let us pay attention to what Micah is saying here, that God must not only strip away things that are bad in themselves, but must also eliminate anything that might foster superstition. Once we have understood that, we will no longer find it strange that Noel is not being observed today, but that on Sunday we will celebrate the Lord’s Supper and recite the story of the nativity of our Lord Jesus Christ. But all those who barely know Jesus Christ, or that we must be subject to him, and that God removes all those impediments that prevent us from coming to him, these folk, I say, will at best grit their teeth. They came here in anticipation of celebrating a wrong intention, but will leave with it wholly unfulfilled.74
73. “In the creation of a festival, an idol, the product of human fantasy, was forged in the name of God.” Leith, 214.
74. Farley, Sermons on the Book of Micah, 302–304."
Cited from, "In Translatiōne: John Calvin’s Letters to the Ministers of Montbéliard (1543–1544): The Genevan Reformer’s Advice and Views of the Liturgical Calendar," The Confessional Presbyterian 13 (2017): 209-210.
"Now, I see here today more people that I am accustomed to having at the sermon. Why is that? It is Christmas day. And who told you this? You poor beasts. That is a fitting euphemism for all of you who have come here today to honor Noel. Did you think you would be honoring God? Consider what sort of obedience to God your coming displays. In your mind, you are celebrating a holiday for God, or turning today into one but so much for that. In truth, as you have often been admonished, it is good to set aside one day out of the year in which we are reminded of all the good that has occurred because of Christ’s birth in the world, and in which we hear the story of his birth retold, which will be done Sunday. But if you think that Jesus Christ was born today, you are as crazed as wild beasts. For when you elevate one day alone for the purpose of worshipping God, you have just turned it into an idol. True, you insist that you have done so for the honor of God, but it is more for the honor of the devil.
Let us consider what our Lord has to say on the matter. Was it not Saul’s intention to worship God when he spared Agag, the king of the Amalekites, along with the best spoils and cattle? He says as much: ‘I want to worship God.’ Saul’s tongue was full of devotion and good intention. But what was the response he received? ‘You soothsayer! You heretic! You apostate! You claim to be honoring God, but God rejects you and disavows all that you have done.’ Consequently, the same is true of our actions. For no day is superior to another. It matters not whether we recall our Lord’s nativity on a Wednesday, Thursday, or some other day. But when we insist on establishing a service of worship based on our whim, we blaspheme God, and create an idol, though we have done it all in the name of God.73 And when you worship God in the idleness of a holiday spirit, that is a heavy sin to bear, and one which attracts others about it, until we reach the height of iniquity. Therefore, let us pay attention to what Micah is saying here, that God must not only strip away things that are bad in themselves, but must also eliminate anything that might foster superstition. Once we have understood that, we will no longer find it strange that Noel is not being observed today, but that on Sunday we will celebrate the Lord’s Supper and recite the story of the nativity of our Lord Jesus Christ. But all those who barely know Jesus Christ, or that we must be subject to him, and that God removes all those impediments that prevent us from coming to him, these folk, I say, will at best grit their teeth. They came here in anticipation of celebrating a wrong intention, but will leave with it wholly unfulfilled.74
73. “In the creation of a festival, an idol, the product of human fantasy, was forged in the name of God.” Leith, 214.
74. Farley, Sermons on the Book of Micah, 302–304."
Cited from, "In Translatiōne: John Calvin’s Letters to the Ministers of Montbéliard (1543–1544): The Genevan Reformer’s Advice and Views of the Liturgical Calendar," The Confessional Presbyterian 13 (2017): 209-210.