At times the Torah states that a person receives arichas yamim, long life, for an act he performed. What is the purpose of arichas yamim? Is it to enjoy this world more? Is it to consume more food, travel the world and the like? The pasuk says למען ירבו ימיכם...כימי השמים על הארץ, in order to prolong your days...like the days of heaven over the earth.
In the last Devarim 11:21. Torah the Belzer Rebbe delivered before his passing on the 21st of Av, he explained that these words tell us what the purpose of arichas yamim is. Arichas yamim (ירבו ימיכם) is there for you to accomplish with your days on this world spiritually with Torah and mitzvos, making them eternal. כימי השמים על הארץ means to live heavenly days on this world!
The Maharil Diskin would visit a widow in Yerushalayim on a regular basis to wish her a Good Shabbos. This widow was paralyzed, confined to a bed, and in an unclean state. One day she asked him for a Bracha for אריכת ימים, long life. This was staggering, as he wondered why she would want to live any longer, considering her state. She told him that once weekly, they send someone from Bikur Cholim hospital who cleanses her body. This is the only time the entire week she can say a Bracha because that is the only time she has a גוף נקי , clean body. She then said, “I wait for this all week. If I have אריכת ימים , I am prepared to live like this for years.”
