Rif Shabbat 12a

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12a

{Shabbat 25 continues}
And his disciples hid the corners of their garments from him {since they did not have tzitzit on them}.
He said to them: My sons! Have I not thus taught you: A linen robe, in respect to tzitzit-Bet Shammai exempt it, while Bet Hillel hold it liable, and the halachah is as Bet Hillel?
But they held, It is forbidden on account of a night garment.
{Since a night garment is exempt, if one wore wool tzitzit fringes, it would be shaatnez. They held Bet Hillel's opinion was as regards Scriptural law, but Rabbinically, it would be forbidden lest one make a mistake with regard to a night garment.}

They learnt {in a brayta}: Rabbi Shimon ben Eleazar said: One may not light [the Sabbath lamp] with balsam.

What is the reason?
Rabbah said: Since its smell is fragrant, there is [the need of] a preventive measure, lest one draw supplies from it.

{Shabbat 26a}
Abaye said to him: Let the Master say, because it is volatile {=explosive and dangerous}?
He said to him: One thing and yet another. One thing, because it is volatile; and yet another, as a preventive measure, lest he draw supplies from it.

The Sages learnt {in a brayta}: One must not feed a lamp with unclean tevel {untithed food} on weekdays, and all the more so on Shabbat. Similarly, one must not light [a lamp] with white naphtha on weekdays, and all the more so on Shabbat.

As for white naphtha, that is well, [the reason being] because it is volatile.
But what is the reason of unclean tevel?
Scriptures state {Bemidbar 18:8}:

ח וַיְדַבֵּר ה, אֶל-אַהֲרֹן, וַאֲנִי הִנֵּה נָתַתִּי לְךָ, אֶת-מִשְׁמֶרֶת תְּרוּמֹתָי: לְכָל-קָדְשֵׁי בְנֵי-יִשְׂרָאֵל לְךָ נְתַתִּים לְמָשְׁחָה, וּלְבָנֶיךָ--לְחָק-עוֹלָם.

8 And the LORD spoke unto Aaron: 'And I, behold, I have given thee the charge of My heave-offerings; even of all the hallowed things of the children of Israel unto thee have I given them for a consecrated portion, and to thy sons, as a due for ever.

{so the pasuk talks of teruma in the plural}
In two terumot the pasuk speaks. One, pure teruma and the other, impure teruma.
Just as pure teruma you may not have of it except after its separation and on, so too impure teruma you may not have of it except after its separation and on.

{Shabbat 27b}

MISHNA:
WHATEVER COMES FORTH FROM A TREE ['ETZ] YOU MAY NOT LIGHT [THE SABBATH LAMP] THEREWITH, SAVE FLAX; AND WHATEVER COMES FORTH FROM A TREE