Fasting · a Light

A companion tested the verse with two threads under his pillow

Surah al-Baqarah tells those fasting to eat and drink until the white thread becomes distinct from the black thread of dawn. Bukhari and Muslim report that Adi ibn Hatim took this literally, put a white string and a black string under his pillow and looked at them in the dark until he could tell them apart, and that the Prophet ﷺ told him it meant the blackness of the night and the whiteness of the day. What he was being pointed at is astronomical twilight: the first horizontal band of light on the horizon before sunrise. Modern timetables fix it by how far the sun is below the horizon, commonly eighteen degrees, and because that figure is argued, printed times for the same city can differ by twenty minutes.

Surah al-Baqarah 2:187

Source · Qur'an 2:187