Our Gemara on Amud Beis discusses the importance of not inflicting excessive fasting and suffering, despite the importance of repentance and abstention when circumstances call for it:
Rabbi Yosei says: An individual is not permitted to afflict himself by fasting, lest he become too weak to work and be beholden to other people, and those people may not have mercy on him. Rav Yehuda said that Rav said: What is the reason of Rabbi Yosei? It is as it is written: “And man became a living soul” (Genesis 2:7). Rabbi Yosei interprets this verse as a command: The soul I placed within you, preserve and sustain it.
This is similar to a famous dictum of Rabbi Elazar Hakappar found throughout Shas, which We also saw repeated earlier on Daf 11a. Even the Nazir, who is presumably abstaining from worldly pleasures in order to achieve a rectification, is still considered to be a sinner in some form. This is because he deprives himself of the pleasures of this world which God has made available to him.
There are numerous formulations throughout rabbinic literature as to how to achieve this balance between abstention and properly and rightfully enjoying the pleasures of the world. (For example, see Mesilas Yesharim 13.) Today, I will share a particularly meaningful and insightful formulation by Rav Tzaddok (Tzidkas HaTzaddik 224), related to the theme of self-sacrifice.
Every day a person must accept upon himself the yoke of heaven in two different dimensions, which are reflected in the two paragraphs of Shema, an absolute kind and a more practical pro-social kind. In the second paragraph of Shema, there is an acceptance of the yoke of heaven within the context of a productive economy. That is, it states, “If you will follow the Commandments then the rains will come on time and the crops will yield their bounty.” This is similar to the position put forth in Gemara Berachos (35b), that though there are exceptional individuals who can completely trust In God's providence and not have to put in any labor, the majority of people must abide by the social contract. Yet, there are a select few who do not make efforts in this world on physical matters and God still provides for them.
Rav Tzaddok understands this as one kind of mesiras nefesh and acceptance of the yoke of Heaven, that is, giving oneself over to the community, and living a life amongst the people. That is all in the second paragraph of Shema. However, there is another element, and that is the total willingness to sacrifice everything, even one’s own life and one’s own welfare. This is represented by the first paragraph of Shema, which is in a singular instead of plural language, and also has the additional clause of love and God with “all your abilities“ “בכל מאדך” because this includes complete and total sacrifice.
Even though one is generally to consider himself in the category of the typical person, who does not throw himself utterly on God, and also must toil to bring in the harvest, a mental bookmark is still made. That is to say, everybody emotionally must start with the first paragraph of Shema, signaling a readiness to make the ultimate sacrifice and live on the highest level. Somehow the person must be ready to perceive a signal from God that this is what he should do, if in his life he is receiving such a calling. But that is an awareness and mental preparation, but on a practical level it is a second paragraph of Shema that is the typical mandate and the daily actions that one must take. And that is to be ready to sacrifice in order to live a God fearing life that is still with the community and in the material world.