3,376. Beginning Hilchos Maaser
Hilchos Maaser 1:1
After separating the terumah gedolah from produce, one separates one-tenth of what’s left; this is called the maaser rishon – first tithe. Regarding this, Numbers 18:24 teaches, Because the tithes of the children of Israel that they will separate to God….” These tithes are given to Leviim, both men and women, as the verse continues, “I gave the Leviim all the tithes of the children of Israel as an inheritance.”
Hilchos Maaser 1:2
A Yisroel (an Israelite) may eat first tithe, and it may be eaten while ritually unclean, because it’s not holy food. When “holy” and “redeem” are mentioned regarding tithes, it’s always regarding second tithe. We see that maaser rishon is secular from Numbers 18:27, “Your terumah will be to you like grain from your granary and the fullness of the vat.” Just as a granary and a vat contain secular produce, once terumas maaser has been taken from the maaser rishon, the maaser rishon is secular produce in all ways. This is why the daughter of a Levi who has been taken captive or who has engaged in prohibited acts of intimacy can be given tithes and eat them. However, if there’s a report that a woman's husband died, or if one witness testified that he died, so she remarried, after which her first husband returned, the Sages penalize her by prohibiting her from eating maaser.