Musar do Pirke Awot 2:1

And King Solomon, peace be upon him, said (Proverbs 13:13), "He who disdains a precept will be injured thereby; and he who fears a commandment will be rewarded." He said this about one who disdains [concern about] light sins. For he will be injured from the angles that we mentioned. "And he who fears a commandment" - to [make efforts not to] negate (fail to perform) a commandment, like he fears from a weighty sin - "will be rewarded": He is destined to receive the full reward [for it]. And our Rabbis, may their memory be blessed, said (Avot 2:1) "And be careful with a light commandment as with a weighty one." And they also said (Avot 4:2), "For the payment for performing a commandment is another commandment and the payment for committing a transgression is a transgression."

The second level is the severity of positive commandments: The foundation of the reward and the root of the recompense resulting from the service is [found] in the performance of positive commandments, as it is stated (Proverbs 13:13), “He who respects a commandment will be rewarded.” And it is [also] stated (Malachi 3:18), “And you shall come to see the difference [...] between him who has served God and him who has not served Him.” And the service [to God] is with commandments that depend upon (involve) actions - whether there is nothing besides the positive commandment or whether there is [also] a negative commandment with them, such as (Deuteronomy 15:7), “do not harden your heart, etc.” (which accompanies the positive commandment of charity). And the commandment of the service will be explained in the Gate of the Service (no longer extant), with God’s help. Nevertheless, there is a manner of reward for the one who is careful not to transgress a negative commandment that reaches [that] of one who does a commandment - such as if the opportunity for a sin comes to a man and he had a desire for a sexual prohibition, but he overcame his impulse - for this is from the essence of the fear of God, may He be blessed. And likewise someone who had the opportunity to get rich by cheating and [charging] interest and there is no one to see and to know; yet he went with innocence and clean hands - his reward for this will be like one who plants righteousness and toils [to do a positive] commandment. And so it is written (Psalms 119:3) “They have done no wrong, but have followed His ways.” And our Rabbis, may their memory be blessed, said (Yerushalmi Kiddushin 1:9), “Since they did not do wickedness, they have ‘followed His ways.’” And we have already discussed the explanation of this verse for you. And our Rabbis, may their memory be blessed, likewise said (Kiddushin 39b), “[If] one sits and does not transgress, he receives a reward as one who performs a commandment, [...] in a case where an opportunity to commit a sinful act presents itself to him and he is saved from it.” And they also said (Berakhot 6a), “‘Those who revere the Lord and esteem His name.’ - this is [a case] where an opportunity to commit a sinful act presents itself to him and he is saved from it.” Even [with] this reward [however], its essence and foundation is [based in] a positive commandment, since he suppressed his impulse with the fear of God, as it is stated (Deuteronomy 10:20), “You must fear the Lord, your God.” And our Rabbis, may their memory be blessed, said (Avot 2:1), “Be careful with a light commandment as with a weighty one, for you do not know the reward for the fulfillment of the commandments.” Yet behold [that] what will be done to anyone who transgresses a negative commandment is explicit in the Torah; and it allocates punishments and statutes and a code for what to do to them. And the punishments are forty lashes, death and expiation at the hands of the Heavens and the four death penalties of the court. But the reward for the fulfillment of the commandments is not explicit in the Torah, so that [people] not prevent themselves from fulfilling the light commandments and involve themselves only in the weighty ones.

And because it is known that the yetzer always stirs up a man to think only of temporal success, the tanna has given us a balm for this, saying (Avoth 2:1): "Weigh the loss of a mitzvah against its gain, and the gain of a transgression against its loss." That is, let one appraise the smallness of the loss that he incurs in this world by performing a mitzvah against the vastness of the eternal, spiritual reward that he will gain in the upper world. And if the yetzer hara invites him to perform a transgression for some pleasure, let him appraise the smallness of the pleasure that he will enjoy from it in this world for a minute time against the vast punishment and eternal suffering that it will cause him.

This is what our sages said: "Know what is above you: an eye that sees, an ear that hears, and all your deeds are inscribed in a book" (Avot 2:1). For since the Holy One, blessed be He, watches over every thing, and He sees everything and hears everything, certainly every action will leave an impression. And all of them are inscribed in a book, whether for merit or for debt (punishment).

The exertion is that which a man completely detaches and removes himself from the physical, and clings always, at all periods and times to his G-d. In this manner, the prophets were called "angels", as said of Aharon: "For a priest's lips shall guard knowledge, and Torah shall be sought from his mouth; for he is an angel of the L-rd of Hosts" (Malachi 2:7), and it is said: "but they mocked the angels (prophets) of G-d" (Divrei Hayamim II 36:16). Even when he is engaged in physical actions required for his bodily side, his soul will not budge from its clinging on high. This is as written: "my soul clings after You; Your right hand supports me"(Tehilim 63:9).

Sixthly, he must think in his heart of all the good things that the Creator, Blessed be He, has done for him from the time of his birth until this day. And he must understand that he should have thanked God for these good things, but that he has not done this, but has transgressed God's commandments. And he should weigh the punishment for the sin against its sweetness and the reward for the good deed against the pain in this world (and in the world to come). As our Sages said, "Reckon the loss incurred by the fulfillment of a precept against the reward secured by its observance, and the profit of sin against its loss" (Aboth 2:1).

The thirteenth principle of repentance is to take seriously the transgressions which one has treated lightly. For example, looking at women or speaking over-much with them, or conversing about idle things, or doing nothing, or mentioning the name of God in vain. All these and many more like them are considered trivial by many people and even by great men of the day — they must be regarded as very serious matters. And there are four reasons for this : First, one should never look at the smallness of the sin but at the greatness of Him who warned against it. A parable will illustrate this. A king commanded his two servants, the one to bring him something to drink for he was very thirsty, and the other to do something that he really did not need very much; and he warned each one, on pain of death. Certainly, if either one of them disobeyed his command he would be liable to death, for they hang a man who has stolen one dinar just as they hang one who has stolen a thousand, for each one has transgressed the command of the king. In the same way the Lord has warned us concerning all of the Torah, "Keep all the commandment which I command you this day" (Deut. 27:1). And it is written, "Cursed be he that confirmeth not the words of this law to do them" (Deut. 27:26). The second reason is that when one transgresses a little matter many times, it becames a very severe matter, because the punishments for each individual transgression are combined. Thirdly, when one is accustomed to commit sins, he comes to regard them as permissible and does not guard himself against them, and he is reckoned among those who cast off the yoke of the Torah and who are "apostates with respect to one matter." Fourthly, it is the way of the evil inclination that after he conquers in some small matter, he goes on to conquer in a serious one. Therefore our Sages said, "Be heedful of a light precept as of a grave one" (Aboth 2:1). And they said further, "For one good deed draws another in its train, and one sin, another sin" (Aboth 4:2).

Our sages of blessed memory summarized this saying: "[what is the proper path a person should choose for himself?] Whatever is harmonious for the one who does it, and harmonious for other people" (Pirkei Avot 2:1). That is, that which leads to the goal of true beneficence, namely, strengthening of Torah and furthering of societal brotherliness.