Generally, tahlil is often recited on Friday night (Thursday night) because that day is believed by Muslims to have extraordinary virtues. It is important to know that Friday night is considered as sayyidul ayyam or the most special day in Islam. Prophet Muhammad SAW even encouraged his followers to actively recite tahlil and surah Yasin on Friday night and day as a recommended form of worship.

This is why we are encouraged to read Surah Yasin and perform tahlil on Friday night for those who have passed away. Not without reason, because this has been explained in a hadith narrated by Abu Dawud as follows: "Surah Yasin is the heart of the Quran, it is not read by someone who seeks the pleasure of Allah except that their sins are forgiven. Recite Surah Yasin for those who have passed away among you." (HR. Abu Dawud, etc.)

Not only that, here is the evidence from another hadith that Friday is a very special day: "The best day on which the sun rises is Friday; on that day Adam was created, on that day he was admitted to Paradise, on that day he was expelled from Paradise, and the Last Hour will take place on Friday. On that day, there is a time when no Muslim stands and prays, asking Allah for something good, but Allah will grant his request." (Narrated by Muslim)