Rebbe says: Which is a straight path that a person should choose? One that is both praiseworthy for the doer and praiseworthy from other people. And be [as] careful with a “light” Mitzvah as with a weighty one, for you don’t know the reward given for [each of the] Mitzvoth. And calculate the cost of a Mitzvah against its reward; and the reward of a sin against its cost. And look at (scrutinize) three things, and you will not come to the hands of sin. Know what is above you: An eye which sees, an ear which hears, and all your actions are written in a book.
We are taught (Chulin 119a) that a person should not take a mother bird in view of her babies (which would violate Devarim 22:6-7) even for the purpose using the bird in the required purification process from leprosy. And the Gemara constructs a “kal vachomer” (afortiori argument). If, for performing a Mitzvah which can be done at little expense (sending away the mother bird), the Torah promises reward of “that it will be good for you and you will have long life” (verse 7), imagine how much reward one will receive for the difficult Mitzvoth.
In light of what we have learned until now, this argument is very difficult to understand. Since we don’t know the rewards for the various Mitzvoth, it is possible that on the easy Mitzvah, like sending away the mother bird, there will be More reward than on a more difficult Mitzvah!
The answer to this question is based on a distinction between the fixed reward for the actual performance of the Mitzvah, and reward that depends on the relative difficulty one had in performing the Mitzvah. We don’t know the amount of reward that any specific Mitzvah carries with it, and it is possible that a “light” Mitzvah earns a greater reward than a “heavy” Mitzvah. It is to this fixed reward that our Mishna refers.
But there is a system of reward that is not connected to any specific Mitzvah, built on the principle “According to the difficulty is the reward” (Ch. 5, Mishna 22). It is in this system that the above Gemara is working. If a Mitzvah that is done with minimal expense and difficulty earns such a great reward for sending away the mother bird (Verse 7), then that same Mitzvah done under more difficult circumstances will certainly bring even greater reward.
The verse (of the reward for sending away the mother bird) must be discussing the reward for the difficulty and not for the actual Mitzvah. For why would it teach us the reward specifically for this Mitzvah and not for any others?! Only because what is being discussed is the reward earned for the difficulty encountered, and this Mitzvah is especially easy.
We see two systems of reward. Reward given for the actual Mitzvah is unknown to us, and it is possible that a “light” Mitzvah receives more reward than a “heavy” Mitzvah. But reward given for the difficulty overcome in performing the Mitzvah is directly related to how difficult that Mitzvah was to perform.
We see this latter system also illustrated in other sources. On the verse (Devarim 12:25) “Don’t consume [blood], in order that it should be good for you and your children after you,” Rashi comments: “See the reward of Mitzvoth! If one who refrains from blood, which is not something that a person craves, both he and his children are rewarded; how much more so is a person rewarded for refraining from monetary and sexual improprieties, which are things that a person craves.” This is not referring to the (fixed) reward for the commandment of refraining from eating blood, but rather to the reward for the difficulty one may have in resisting the desire to consume blood under certain circumstances.
It is this reward that is mentioned in the Torah with the words “in order that it should be good.” If it was referring to the reward for the actual Mitzvah, why is it mentioned here and not in other Mitzvoth? Furthermore, there is no reward given for refraining from the violation of a negative command, for the person didn’t Do anything. The only reward possible is for the difficulty one encountered in refraining from that violation. This is taught to us in the following source (Kiddushin 39b): “One who performs (even) one Mitzvah has good bestowed upon him. [And the Talmud raises a question] Is this only true for fulfillment of a positive command? Is this not also true for not violating a negative command? Isn’t it taught that a person who sits (passively) and doesn’t violate a negative command is given reward like one who performed a Mitzva?! [And the Talmud responds] When a sin presented itself.” This means that there is no inherent reward in the observance of a negative command. However, when the opportunity to violate a prohibition presents itself, and the person is attracted to it, but he controls his desire, he receives reward as if he had fulfilled a Mitzva. (This is clearly speaking about the reward that is received for the difficulty one had in fulfilling the will of G-d.) The Mishna (Peah, Chapter 1, Mishna 1) which teaches “These are the Mitzvoth that man benefits from the “fruit” in this world, while the “principal” is preserved for the next world” sounds like the reward is known! The Mishna is only teaching a distinction between this group of Mitzvoth, which receive their reward both in this world and in the next world, while other Mitzvoth have their reward limited to the next world. But there is no implication of the quantity of the reward, and in fact the reward which is only given in the next world for a certain Mitzva could be so great as to outweigh the reward given both in this world and the next world for a different Mitzvah.
The continuation of that Mishna, “And the study of Torah is equivalent to all of them,” certainly implies knowledge that the reward for Torah study is greater than for any Mitzvah. For what our Mishna is telling us is our inability to know the reward of one Mitzvah relative to another Mitzvah. But the reward for Torah study is certainly greater than for any Mitzvah.
(This should raise the question of why not study Torah all day, in place of doing any other Mitzvoth, since we KNOW that Torah study has the most reward. The fact that we aren’t supposed to work for the reward, as we learned in Ch. 1, Mishna 3, doesn’t really answer the question, since once we know that G-d gives the greatest reward for Torah study, then this must be the best activity. Why doens’t it override the performance of all other Mitzvoth?
(The answer is fundamental to the understanding of the role of Torah study in Judasim. Torah was given “lilmod v’laasoth,” to study and perform. Chazal derive that Torah has to be studied In Order to perform. Studying because it is interesting, stimulating, or rewarding — with no intention of implementing what is learned — is not “Talmud Torah,” true Torah study. In fact, some very harsh words are found in Chazal about one who studies with no intention of implementing what is learned. So, if one studies about lulav, davening, blessings, monetary ethics, lashon hara, etc., but does not take a lulav on Sukkoth, daven in the morning, return a lost object to its owner, etc., all because one is studying Torah — then one has studied Torah without intention to fulfill what is studied. It is a deficiency in the Torah study if it is not implemented when the opportunity arises.)
The reason why a “light” Mitzvah could have more reward than a heavy Mitzvah is because reward for a Mitzvah is a function of the attachment (“dveikuth”) that Mitzvah creates between the doer and G-d. It is possible that an easy or a light Mitzvah could well create a greater attachment than a heavy or difficult one, since the difficulty is a function of man’s abilities, while the attachment to G-d is related to the objective essence of the act. (These realities are part of the hidden aspects of creation…)