In the Torah’s account of the Tribe of Levi it reviews the tragic deaths of Aaron Hakohen’s righteous sons, Nadav and Avihu. On this occasion it adds a hitherto unmentioned detail - that they died without any sons. The Gemara extrapolates from here that had they had sons then they would not have died. The Chasam Sofer zt”l explains that Nadav and Avihu had reached such a high level of closeness to Hashem that they had fulfilled their potential, and there was no further need for them to live in Olam Hazeh. However, had they had children then they would have been needed to stay alive in order to bring them up and provide for their needs. We learn from here that even if a person reaches total perfection in his own personal Avoda, he is nevertheless kept alive so that he can benefit his children. Moreover, it seems from the yesod of the Chasam Sofer that there are two levels in Avodas Hashem - the first is a person’s development of his Torah, midos and relationships to Hashem, and the second, his responsibility to his children. In the ‘pisuchay chosam’, the Chasam Sofer adds that a great tzaddik can be kept alive in order to guide his talmidim as well as his children, implying that a person‘s second stage of Avoda is not limited to helping his children, but also his talmidim.
We find an example of the dualistic nature of Avodas Hashem in Parshas Vayishlach. After Yaakov Avinu emerged from the tremendous challenges of living with Lavan and facing his hostile brother Esav, the Torah describes him as being ’shalem’ - Chazal understand this to mean that he was spiritually complete; he had withstood the spiritual threats of Lavan and Esav and emerged totally pure of any lacking. Yet, the rest of his life was plagued by the difficulties he endured as a result of the mistakes and shortcomings of people around him - his daughter’s lack of tznius in going out resulted in her abduction by Shechem and its eventual destruction by Shimon and Levi. This was followed by the incident with Reuven moving Bilhah’s bed, and the sale of Yosef. It is striking that after emphasizing Yaakov’s individual greatness, it then outlines in great depth the imperfections of the world around him. This shows us that whilst he had completed his own personal Avoda, he remained on this world in order to rectify the lacking of those around him.
Many Gedolim spent a great portion of their lives focused largely on their own personal avoda, but when the time was right, they devoted great amount of energy into serving the Jewish people. Rav Shach zt”l is a perfect example of this, he continuously for many years but when he emerged as a Gadol he totally devoted himself to Klal Yisroel, and never turned away people in need of his help.
The two forms of Avoda also require two different attitudes and approaches; this is demonstrated in the creation of mankind. Whilst all the animals were created in one maamer, man and woman were created in two separate maamarim (sayings); my Rebbe, Rav Yitzchak Berkovits Shlita explains that each maamar represented a new stage in creation. The maamar creating man represented the aspect of man’s avoda as an individual and his relationship with himself. The maamar creating woman led to a new stage of creation known as society, whereby man has to interact with those around him. These two stages require very different mindsets - with regard to his attitude towards himself, man has to apply a certain degree of din on himself., involving self-analysis an striving to improve oneself. When he endures suffering he should stress the need to trust in Hashem and to strive to improve his ways. In contrast, man must have a very different view towards other people - when someone else suffers, he must not tell them that it is all from Hashem and that they should strive to grow, rather he should focus on caring for them and acting as if they are not being looked after by anyone, including Hashem. The Brisker Rav zt’l made this point in a remarkable way. He posited that every negative trait has a positive aspect to it - when asked what was the positive aspect of the trait of kefira (denying G-d), he answered that it helps us act properly when out friend is in need. We cannot tell him to have trust in Hashem that everything will be fine, rather we must act, so to speak, as if G-d is not involved in his life and we must take responsibility.
Gedolim also demonstrated a dualistic attitude in their lives - to themselves they were demanding and self-critical, hiding from kavod and refusing help from other people, but to their fellow man, they were kind, caring, tolerant, and full of praise. Nadav and Avihu never had the responsibility of guiding others, and therefore their avoda was limited to self-perfection. May all of us merit to perfect ourselves in both levels of Avodas Hashem - perfecting ourselves and the world around us.
 Bamidbar, 3:4.
 Yevamos, 64a.
 The ‘pisuchey chosam’ was written by the Chasam Sofer’s grandson, but it was based on the teachings he learnt from his grandfather.
 This concept is supported two passukim earlier where the Torah describes Moshe Rabbeinu’s talmidim as his children. Rashi explains that because he taught them it is considered as if he gave birth to them. Thus, just as a person has an achrayus to guide his physical children, he must do the same for his spiritual ‘children’. It seems clear that Nadav and Avihu did not have any talmidim who perhaps could have been cause for their lives to be prolonged.
 As always, we must realize that the Torah is talking to us on a level that we can understand - it focuses in on Deena’s chisaron in tznius to teach us a lesson, but in truth, her lacking in that area would be largely discernible to us.
 Heard from Rav Efraim Kramer Shlita.
 Needless to say we must not forget that Hashem is in truth guiding everything, however there can be a yetser hara to avoid helping people by saying that ‘G-d will provide’ - this is clearly an incorrect attitude.