When does the one in i'tikaf (spiritual retreat in the mosque) enter, and when does he exit?

The questioner : The questioner asks: When does the one in i'tikaf exit his retreat according to the Shari'ah? Is it on the night of the festival, meaning after the sun sets, or after the Fajr prayer on the day of the festival? Please provide the evidence or the definition.

The Shaykh : Well, the one in i'tikaf exits when Ramadan ends. And when does Ramadan end?

The questioner : When it sets.

The Shaykh : The sun sets on the night of the festival. So, when the sun sets on the night of the festival, the time for i'tikaf ends. Similarly, the one in i'tikaf enters when the sun sets on the night of the twentieth of Ramadan. The last ten days begin when the sun sets on the night of the twentieth of Ramadan and end when the sun sets on the night of the festival.