Saying takbir on Eid al-Fitr not only marks the end of the month of Ramadan, but also welcomes the day of victory.
Saying takbir or takbiran is an action recommended in Islam when celebrating holidays, including Eid al-Fitr.
The takbir reading during Eid al-Fitr is read from the evening of 1 Shawwal until the next morning, precisely when the Eid al-Fitr prayer priest reads the takbiratul ihram. A number of other opinions say that the deadline for reading the takbir prayer is until the Eid al-Fitr prayer.