This print is of John Calvin fencing the Lord's Table against the Libertines, refusing them access. The following quote is from the Desiring God website:
One of the most persistent thorns in Calvin's side were the Libertines in Geneva. But, here too, his perseverance was triumphant in a remarkable way. In every city in Europe men kept mistresses. When Calvin began his ministry in Geneva in 1536 at the age of 27, there was a law that said a man could keep only one mistress (see note 37). Even after Calvin had been preaching as pastor in St. Peter's church for over fifteen years, the immorality was a plague, even in the church. The Libertines boasted in their license. For them the "communion of saints" meant the common possession of goods, houses, bodies and wives. So they practiced adultery and indulged in sexual promiscuity in the name of Christian freedom. And at the same time they claimed the right to sit at the Lord's table (see note 38).
The crisis of the communion came to a head in 1553. A well-to-do Libertine named Berthelier was forbidden by the Consistory of the church to eat the Lord's Supper, but appealed the decision to the Council of the City, which overturned the ruling. This created a crisis for Calvin who would not think of yielding to the state the rights of excommunication, nor of admitting a Libertine to the Lord's table.
The issue, as always, was the glory of Christ. He wrote to Viret, "I . . . took an oath that I had resolved rather to meet death than profane so shamefully the Holy Supper of the Lord. . . . My ministry is abandoned if I suffer the authority of the Consistory to be trampled upon, and extend the Supper of Christ to open scoffers. . . . I should rather die a hundred times than subject Christ to such foul mockery" (see note 39).
The Lord's day of testing arrived. The Libertines were present to eat the Lord's supper. It was a critical moment for the Reformed faith in Geneva.
The sermon had been preached, the prayers had been offered, and Calvin descended from the pulpit to take his place beside the elements at the communion table. The bread and wine were duly consecrated by him, and he was now ready to distribute them to the communicants. Then on a sudden a rush was begun by the troublers in Israel in the direction of the communion table. . . . Calvin flung his arms around the sacramental vessels as if to protect them from sacrilege, while his voice rang through the building:
"These hands you may crush, these arms you may lop off, my life you may take, my blood is yours, you may shed it; but you shall never force me to give holy things to the profaned, and dishonor the table of my God." "After this," says, Beza, Calvin's first biographer, "the sacred ordinance was celebrated with a profound silence, and under solemn awe in all present, as if the Deity Himself had been visible among them" (see note 40).
To learn more about this controversy, you might consider reading Calvin's Treatise against the Anabaptists and against the Libertines. There are numerous used copies available on Amazon.com: