R. Yonah: Often they add to a man's years due to an act of Tzedakah ¹ .

Malbim: Derech is the big path for the Rabim from city to city. Orach separates from the big paths to the villages. Nesiv is for individuals. Tzedakah - Mitzvos Bein Adam la'Makom - goes on Orach. It is not a general path [for everyone]; it is for people of [Hashem's] creed, that He sanctified them with His Kedushah. There is life in this path, both in this world and in the world to come - "Asher Ya'aseh Osam ha'Adam va'Chai Bahem" (Vayikra 18:5).

Rashi: [One who goes on] the path of Tzedakah will not die.

R. Yonah: Clearly, the years of a Ba'al Tzedakah will not be shortened. It will shield and save him!

Malbim: Tzedakah has a Nesiv in which individuals went, e.g. Moshe and Eliyahu and those like them, who became sanctified like angels. "Tzidkas Hashem Asah" (Devarim 33:21) - his Tzedakah was constant, like Tzedakah of upper beings that do not die; death did not rule over them. They entered [to dwell] among the upper beings while alive, like Eliyahu, or died via Neshikah, like Moshe. Even though when they separated from physicality and went among the upper beings, they came to the Derech for the upper beings, which is called Derech, while they were in their physical 'garments' (bodies) it is called Nesivah, for such elevated people are few. One who goes on the individual Nesiv to the Derech, to be paths for him among those who exist forever, he does not find death at all.