Rav Kook is big on the idea (based on Yoma 86) that if a person sins, and then that sin motivates him to teshuvah and growth, then the sin is shown to have been positive. This is part of a worldview which sees everything in our universe as possessing some positive aspect and redeemable character.
Lately, I’ve been contemplating the relationship between this outlook and the concept of מצוה הבאה בעבירה (mitzvah haba’ah ba’aveirah), the rule that a mitzvah enabled by a sin is not a mitzvah. For example, the gemara (Succah 29b-30a) rules that one may not use a stolen lulav on Succos, even after the original owner has abandoned hope of claiming it, because he possesses it only as a result of sin.
The disqualification of מצוה הבאה בעבירה would seem to argue that evil is not redeemable; once an evil has been committed, it and its product are forever corrupt.
However, there are several different formulations of this מצוה הבאה בעבירה principle and its application, because the rule does not seem to be applied uniformly in the Talmud and halachah. Examples of its uneven application include:
• A stolen succah may not be used, but because of a sentence in the Torah rather than because of מצוה הבאה בעבירה (Succah 9a);
• A lulav from a tree that has been worshipped as an idol may be used (Succah 31b);
• One may not remove the berries from a hadas on Yom Tov, because that makes the hadas eligible for use – but if one did so, one may then use the hadas for its mitzvah (Succah 32b, as resolved in Rambam Hilchot Lulav 8:5);
• One may fulfill the mitzvah of procreation by producing a mamzer, at least according to some authorities (Yevamot 22a; Rama Even haEzer 1:6; but note apparent dissension in other authorities);
• Aravah branches picked by a non-Jew on Shabbat for a Jew may be used (Mordechai Succah 747).
1. Tosafot (Succah 30a) offers one formulation: A mitzvah may use an object with which sin has taken place, like a lulav from a tree that has been worshipped. The only limit is that the mitzvah may not be enabled by the sin.
This seems logical, but aside from flying in the face of Rav Kook’s optimistic view that sin enables good when it promotes teshuvah, it also flies in the face of the acceptable hadas which was de-berried on Yom Tov.
2. Shaar haMelech (to Hilchot Lulav 8:5) offers a second formulation: A mitzvah may be enabled by an aveirah. The only limitation is that the same action cannot involve both mitzvah and aveirah.
So a previously de-berried hadas, or a previously-worshipped lulav, or an aravah picked on Shabbos, is fine. On the other hand, one may not use a stolen lulav, since the act of using it is an act of failing to return it to its rightful owner.
This also seems logical, and it mirrors the concept of אין קטיגור נעשה סניגור, that the same entity [or, in this case, action] cannot be both agent of sin and agent of merit [eg gold from the Golden Calf cannot be used for atonement in the Holy of Holies on Yom Kippur].
To put this into Rav Kook's framework: Evil can be redeemed, but first one must abandon the evil.
3. The Yalkut haGershuni (cited in Sdei Chemed מ:עז:כו) suggests a third formulation: Evil cannot be used for a mitzvah because disobeying Gd contradicts the obedience of mitzvot. However, where the Torah defines a mitzvah purpose beyond obedience, and that purpose is not contradicted by the evil, then the product of that evil may be used for the mitzvah.
So a stolen lulav may not be used for Succot, because the nature of the mitzvah of picking up the Arba Minim is to demonstrate loyalty to Gd, and one who is loyal to Gd would not steal.
On the other hand, a stolen succah would not run afoul of מצוה הבאה בעבירה, since the Torah specifies that we sit in the Succah to remember the Divine protection in the desert. Stealing does not contradict remembering Gd’s protection in the desert.
Similarly, one who ate chametz on the afternoon before Pesach broke the law, but also fulfilled the mitzvah of eliminating chametz. The Torah’s goal is to eliminate chametz, and the fact that he ate chametz does not contradict the Torah’s defined good.
I'm not sure how to apply this to Rav Kook. To some extent I feel that sin automatically contradicts teshuvah - the goal of teshuvah is to draw close to Gd, and sin takes us in the opposite direction. But I'm not sure.
This idea is fraught with problems both technical (the disqualification of stolen matzah) and ethical (are we to read the Divine mind regarding its purposes?), but it’s still interesting.
The bottom line: Unless we adopt Shaar haMelech's formulation, the מצוה הבאה בעבירה disqualification seems to be a real challenge to Rav Kook’s rosy view of teshuvah.