The Mishna (27b) teaches that there are cases where a person can take a neder in order to protect his interests, and the halakha recognizes that this vow was taken in order to deceive and is not a true neder. The specific cases in the Mishna are situations where a person takes a vow that the merchandise in his possession is teruma or belongs to the king. This is done in order to keep haragin (people who may kill you and take your money), haramin (robbers) and mokhsin (tax collectors) from taking valuables from them.
With regard to tax collectors, our Gemara points to Shmuel’s ruling that dina d’malkhuta dina – that we must follow the rules of the government – and questions how the Mishna can accept that a person may lie to avoid paying taxes. Two answers are suggested by the Gemara:
- Shmuel is quoted by Rav Hinnana in the name of Rav Kahana that this is only true in the case of a tax collector who does not follow the rule of law, but takes as much as he sees fit.
- Rabbi Yannai suggests that our Mishna is talking about a self-appointed tax collector, who is not operating with government approval.
The situation of a mokhes – a tax collector – was different in Talmudic times than it is today. In those days (and in some places this was true until fairly recently) the right to collect taxes was leased by the government to individuals who would then collect taxes in the name of the government. The individual who purchased this right from the government would then assign others to collect the taxes and pay him a percentage of the receipts. There was a lot of room for cheating and dishonesty given the situation was that tax collection was a business, and the more that was collected, the more profit was made. Thus, the mokhes could choose to forgive the debts of his friends and relatives entirely, choosing to collect more than was appropriate from those people with whom he did not have a relationship. It is for this reason that the Talmud often presents the mokhes as equivalent to a robber.