Demai 7:2 - 7:3

מזגו לו את הכוס – [cup of wine] on the Sabbath day.

אומר וכו' – it is not enough for him for what he stipulated from the Eve of the Sabbath (i.e., on Friday), but he needs to once again say on the Sabbath: “When I come to eat and to drink what I shall leave [at the bottom] from the cup [of wine],etc.” In the Jerusalem Talmud, an objection is raised if when he says “from now it will be heave-offering,” for everything is mixed together and it becomes מדומע /mixed with heave-offering/Terumah in proportions sufficient to make the whole prohibited to non-priests (i.e., mixing secular with sacred things), and if when he says, “when I drink it” – it was not heave-offering, but only after that he drank it, and it was found that he was drinking eatables forbidden pending the separation of priestly gifts, and it answers that when he says, “from now and when I will drink it, it will be heave-offering,” and it is found that he didn’t drink eatables forbidden pending the separation of priestly gifts and also that it was not something mixed with heave-offering in proportions sufficient to make the whole prohibited to non-priests.

בפיו – in the mouth of the cup.

שאינו מאמין לבעל הבית – on the tithes.

וחושך גרוגרת אחת - he is prevented from eating one dried-fig corresponding to that of the heave-offering of the tithe [that the Levite gives to the Kohen] that he set aside, in order that he would not steal from the owner of the house.

לא יחשוך (he should not diminish/withhold) – and purchase one dried-fig and eat for if he didn’t eat, he would be starving himself and he would diminish from his meal and it is found that he would diminish through this the work of the owner of the house for he is not able to perform his labor.

לא יחשוך מפני שהוא תנאי בית דין – that the heave-offering of the tithe will be from the owner of the house and the Second Tithe from the worker, therefore, the owner of the house is obligated to give him the dried-fig that he set aside for tithing the heave-offering of the tithe.