Sotah, Chapter Two, Mishnah Two
The mishnah continues to describe the Sotah process. This mishnah is an expansion of that described in Numbers 5:17.
1) [The priest] takes an earthenware bowl and pours half a log of water into it from the laver.
a) Rabbi Judah says: a quarter [of a log].
b) Just as [Rabbi Judah] reduces the amount of writing, so he reduces the quantity of water.
2) [Then the priest] enters the temple and turns to his right and there was a place there [on the floor] that was a cubit by a cubit, and a marble tablet, to which a ring was attached.
a) When he would lift this up, he would take some dust from beneath it which he puts [into the bowl] so that it would be seen on top of the water; as it is said, And of the dust that is on the floor of the Tabernacle the priest shall take, and put it into the water (Numbers 5:17).
Section one: We should note that the mishnah is now beginning to follow the order of the verses which describe the Sotah ritual in Numbers 5. Verse 15 describes the minhah sacrifice (yesterdays mishnah) and verse 17 describes the water in the earthenware bowl, into which the name of God will be rubbed out. The verse only says that the priest takes some water, but it does not say where he takes it from. The mishnah adds that it is taken from the laver (the sink, for those of you who speak normal English). There is a debate about how much water is to be put into the bowl, but in either case the amount of water is just sufficient to absolve the ink from Gods name. Rabbi Judah gives a smaller measurement for the water since he prescribes the least amount of writing (see tomorrows mishnah).
Section two: The Torah states that the priest should take some dust from the floor of the Tabernacle and put it into the bowl. In the Temple floor was a special tile with a ring attached to it so that the priest would have dirt available. The priest would pull on the ring, lift up the tile and take from the dust underneath. In other words, the Temple was built so that this ceremony could take place with relative ease. As far as the function of the earth, it seems likely that it was considered to be imbued with a certain holy power that would aid in testing the guilt/innocence of the Sotah.