Subscribe to the Daily Daf Yomi Summary here.
Rav Pappa said to Rava: My master should see how the rabbis pay the head tax for others, and then they work them excessively. Rava replied: I might have died without ever having told you this thing: Rav Sheishes said: The seal of bondage of these people lies in the king’s archives, and the king has decreed that he who does not pay his head tax should be made the servant of the one who pays it on his behalf.
Other Rishonim explain this Gemora differently: they say that the rabbis violated the prohibition of ribbis. This is because they paid the tax for their poor brethren, and by working them excessively, they were paid back more than what they laid out.
The Radvaz asks: How can the principle of “the law of the land is the law” trump the prohibition of subjugating a fellow Jew excessively?
He answers that since the excessive work is not regarded as money, for by law, they are obligated to serve them; the prohibition falls off by itself, for if there is no loan, there cannot be any ribbis.
The Ritva writes that by paying their taxes to the king, they acquire them as slaves until they are repaid; the money is not regarded as a debt at all.