This question is asked by the Tiferes Yisrael here Boaz #2.

1) He answers that the problem of chavilos chavilos only applies when one person does 2 actions at the same time. For instance, the Gemara Sotah 8a states that the Cohen cannot give the bitter waters to drink to 2 Sotah ladies at the same time because this would be chavilos chavilos. On the other hand, if one does one action, and through this action one fulfils 2 Mitzvos, there is no problem of chavilos chavilos. Therefore when one burns the tamei oil and through this one action of burning, one performs 2 Mitzvos (a) burning tamei Terumah and (b) lighting Shabbos candles; there is no problem of chavilos chavilos.

2) The Tiferes Yisrael asks on his own answer from Gemara Pesachim 102b which states that one may not say both Kidush and Birkas Hamazon on one cup of wine because of chavilos chavilos. Why do we not say that there is only one action here; with one cup; so it should be in order?! Tiferes Yisrael answers that Kidush and Birkas Hamazon are considered as 2 actions, because Kidush and Birkas HaMazon are 2 quite different Mitzvos. This is tantamount to 2 actions performed simultaneously on 1 cup of wine. This is different than burning the tamei terumah; where one does only one action which has 2 results and is therefore not called chavilos chavilos. Tiferes Yisrael compares this to Kidush and Havdalah which we make on the same cup when Yomtov falls on Motzaei Shabbos. Kidush and Havdalah have a similar purpose; to separate between one day and the next day. Therefore this is considered as only one action and there is no problem of chavilos chavilos.

Josh, when people ask a question asked by the Mefarshim, I often say "Baruch She-kivanta!". In fact, your question is asked by the Maharit Algazi and several other Achronim. However, I am now going to cite Rav Yosef Shalom Elyashiv zt'l who says that this question is "not a question at all"!

I will try and explain, bs'd.

This is from the "Notes of Rav Elyashiv" on Sotah 8a, on the Gemara that I cited above, that the Cohen should not give two Sotas to drink the waters together. It is at the top of page 54 of the sefer DH Chavilos.

Rav Elyashiv says that if one would say that there is a problem of chavilos chavilos when lighting Shabbos candles with tamei terumah, then one will also have to say that a Cohen should not eat Matzah made from Terumah on seder night to fulfil the Mitvah of eating Matzah.

What Rav Elyashiv means is that there is a Mitzvah for a Cohen to eat Terumah. This is stated in Gemara Pesachim top 73a; that the Mitzvah of eating Terumah outside Yerushalayim is equivalent to doing Avodah in the Beis Hamikdash. The Rambam in Sefer Hamitzvos, positive Mitzvah #89, writes that eating Terumah is included in the Mitzvah of eating Kodashim.

Now we look at the Mishnah Pesachim 35a which states that a Cohen can fulfil the Mitzvah of eating Matzah on Pesach by eating Matzah made from Terumah. Nobody says that he should not do so lecatchilah because of chavilos chavilos.

Rav Elyashiv explains that the reason there is no problem with this is because by doing the Mitzvah of eating terumah one automatically derives benefit from the terumah. That is the way one does the Mitzvah. If so, there is no problem if one does another Mitzvah whilst one is also enjoying the Terumah.

Similarly, one is allowed to enjoy the use of tamei Terumah. One can use it as fuel to cook one's meals. Just as one may use it to cook one's meals, one clearly may use it for lighting Shabbos candles, and the fact that Shabbos candles reperesent a Mitzvah does not make a difference.

Behatzlachah Rabah

Dovid Bloom

Josh, this is a brilliant idea!

1) However, there may not be a problem of chavilos chavilos when one lights the 2 candles both as Shabbos and as chanukah candles, but there are different problems involved. We pasken (Shabbos 21b and Shulchan Aruch Orach Chaim 673:1) that one may not use the Chanukah candles for mundane purposes. On the other hand, the Gemara Shabbos 23b states that the Mitzvah of the Shabbos candle is for peace in the home, and Rashi 25b DH Hadlokas writes that wherever there is no candle there is no peace because one walks along and trips up in the dark. Hagohos Bach #3 writes that one will have to eat in the dark.

2) So one is not allowed to derive benefit from the Chanukah candles, whilst the whole purpose of the Shabbos candles is to derive benefit from them. How could it be possible to light candles both as Shabbos and as chanukah candles, since we know that they have the opposite aim?!

3) In addition, Rashi Shabbos top 21b DH veAsur writes that the reason one may not derive benefit from chaukah candles is because by doing so, it becomes no longer noticeable that it is the candle of a Mitzvah. I argue that if one lights the candles both as Shabbos candles and as Chanukah candles, it is no longer noticeable that they have been lit in order to be Mitzvah candles, because people will think that they have merely been lit in order that one should not trip up on Friday night on the sticks and stones lying around the house (see Mishneh Berurah 263:3).

A freilicher chanukah

Dovid Bloom

Further comment:

1) The question of the person with only 2 candles on the second night whch falls on Shabbos, is almost the same as what Rava said in Shabbos 23b that if a poor person only has enough money for only one candle, then the Shabbos candle takes priority because of Shalom Bayis. We see that Rava did not entertain the possibility that one can fulfil both Shabbos and Chanukah candles simultaneously. The reason is because of what I wrote above; that one may not derive benefit from the Chanukah lights. According to this, someone with only 2 candles, should light one for Shabbos (he will not be yotzei the inyan of Zachor and Shamor with 2 candles, but there is no choice here) and one for Chanuka (he will not carry out the Mitzvah of Mehadrin to light 2 on the 2nd night but he is yotzei the basic Halacha).

2) However the Magen Avraham 678:2 writes that in places where chanukah candles can only be lit indoors, it is possible that Rava on 23b would agree that the pauper who can only buy one candle should buy a chanukah candle. He will not have to sit in the dark, because even though one is not allowed to eat to the light of the chanukah candles, here there is no choice. This is comparable to the times when it is dangerous to light in the window, so one places it on the table, even though inevitably one will benefit from the light, as the Ran writes. We learn from the Ran that where there is no other choice, one may enjoy the chanukah candle. According to this we can argue that the person with 2 candles on the 2nd night on Shabbos, also has no choice, so he could have intention to light them as Chanukah candles too.

3) As regards to the problem of chavilos cahvilos, I argue that Rashi Sotah 8a DH Chavilos writes that the reason this is no good is because it looks as if the Mitzvos are a burden on oneself and one is trying to make life easy and do them all in one shot. This would not apply to someone who only has enough oil for 2 lights. He would love to light 4 candles on the second night on Shabbos, but he is simply ????.

Chodesh Tov

Dovid Bloom