ما هو الإمساك؟

Abstaining from things that break the fast, such as eating, drinking, and sexual intercourse, is not obligatory until dawn, based on Allah's saying: "And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]" (Quran 2:187), and the Prophet's (peace be upon him) saying: "Indeed, Bilal calls the Adhan (definition) at night, so eat and drink until Ibn Umm Maktum calls the Adhan." Some scholars have recommended abstaining before dawn as a precaution.

As for abstaining after the Maghrib Adhan as a precaution, it is not recommended. Rather, what is prescribed is to hasten breaking the fast upon hearing the Adhan, based on the Prophet's (peace be upon him) saying: "When the night approaches from this side, and the day retreats from this side, and the sun sets, then the fasting person breaks his fast," and his saying: "People will continue to be upon goodness as long as they hasten breaking the fast."