“The Imām’s Final Letter” - Muharram 1446, Night 21 - IMIEC (MD)

What was the content of perhaps the last letter which al-Imām al-Husain (peace be upon him) wrote, before reaching martyrdom? How can we understand this letter? How can we learn from this letter & apply what we learn in our lives?
Note: Something I wish to clarify, is that with what I mentioned in this lecture, I don't mean to say the Dunyā is useless. On the contrary, it is our way to Heaven, & is the place in which we can worship & obey Allāh (exalted be He). Rather, what I mean to say is that it should not be our goal. Rather, we should see it as a tool to reach the highest ranks in the Ākhirah.