Does i'tikaf (spiritual retreat in the mosque) begin on the night of the twenty-first or on the dawn of that day?

The questioner : The questioner says: Honorable Shaykh, do you know the speech?

The Shaykh : Where is the Honorable Shaykh?

The questioner : Honorable Shaykh, does i'tikaf (spiritual retreat in the mosque) begin on the day of the twenty-first or on the night?

The Shaykh : Yes, what did you say? What did you say?

The questioner : He says: Can the target be the twenty-first day or the night?

The Shaykh : The majority of scholars hold that i'tikaf (spiritual retreat in the mosque) begins on the night of the twenty-first day, not on the dawn of the twenty-first day. Some scholars, however, held that i'tikaf begins on the dawn of the twenty-first day, citing the hadith of A'ishah (may Allah be pleased with her) in al-Bukhari: "When he prayed the Fajr prayer, he entered his place of i'tikaf." The majority responded to this by stating that the Messenger (peace and blessings be upon him) separated himself from the people in the morning, whereas the intention for i'tikaf is from the beginning of the night. For when do the last ten days begin?