In his first speech after arrival in the holy city of Najaf, Imam Khomeini stated thus to the theology students:
“Think of it from now; think of it while you are still young;
now every step that you take is in the direction of the grave;
every minute of your noble life that passes brings you to an extent closer to the grave (to death);
to where you are going to be interrogated (in the grave);
reflect on this subject (which is that) of getting close to the grave (to the hour of death);
and nobody has given you a written assurance that you will live for a hundred and twenty years.
A person can die at the age of twenty-five, or die right now.
There is no guarantee and you must be careful,
and purify yourself spiritually (while you are still young and have the time).”
Narrated by: Hujjat al-Islam wal Muslimeen Sayyid Hamid Rouhani
Taken from: Impressions from Imam Khomeini’s Memoirs, vol. 5, chapter 7, pp. 179-80