"Human tears are an expression of suffering. But they can also be a source of ritual impurity if they are shed by someone who has the status of a zav whose liquids are spiritually contaminating.

To prove that tears are considered a liquid, the gemara cites the passage which describes the suffering inflicted by G-d on His people in exile as "You have given them to "drink" a shlish measure of tears." (Tehillim 80:6)

What is meant by the use of the term shlish, which can mean either a third, the third or threefold?

In his commentary on Tehillim Rashi offers an explanation for each of these options.

One is that this is a reference to the Babylonian exile which lasted for only seventy years, a third of the 210-year exile in Egypt that is described in the first part of the above-mentioned passage as "You have fed them with the bread of tears."

There is a second approach that this is a reference to the exile of the Hellenist Greeks which was the third of the four exiles which span Jewish history.

Finally, there is the Midrash which relates this passage to the three tears shed by Esav when he was told by his father Yitzchak that the blessings intended for him had been conferred by mistake upon his brother Yaakov. "He cried with a great and bitter cry" (Bereishet 27:34). He was then blessed to live by his sword and to have dominion over his brother and his descendants when they are not faithful to their G-d.

A final note on the historical hints contained in this passage was provided by Rabbi Samlai (Sanhedrin 97b) who attempted to calculate the duration of the current fourth exile. His target date has long passed as have those of other calculators throughout history, failures which caused our Sages to discourage calculations when Mashiach will arrive and to patiently look forward to his arrival.

The Kutim in the time of the Mishna were considered genuine converts to Judaism who observed only the mitzvot which were explicit in the Written Law but not those of the Oral Law. These descendants of the heathens, who the Assyrian ruler Sancherib brought to Samaria (hence the name Samaritan) to replace the ten tribes of Israel he had exiled, were eventually excluded from the Jewish nation when it was discovered that they had continued their idol worship and that their conversion was not genuine.

During the Mishnaic period the Kutim could only be trusted to testify about a matter of religious observance in which they themselves believed. Our Mishna (56b) lists as one of those matters the testimony they provided about the location of graves where humans were buried by placing a marker there. They could be relied on that an unmarked area was free of this ritual contamination.

But how, asks the gemara, could they be relied on in regard to marking graves when the obligation to do so is not Torah Law but of rabbinic authority which they did not recognize?

The answer given is that there is a passage in the prophecy of Yechezkel (39:15) which speaks of travelers in Eretz Yisrael who "will see the bone of a dead man and place a marker there". This passage, which constituted Written Law for the Kutim, is part of the prophecy of Yechezkel about the purification of the Holy Land which will be carried out after G-d destroys the armies of Gog and Magog who will invade the country. There will be so many corpses that a massive effort will be made to locate and bury them. The markers will serve as an identification of a place where there are remains of the dead which will be buried in time by the Anshei Tamid (ibid. 39:14).