What are the pillars of fasting?

The questioner : What are the pillars of fasting?

The Shaykh : Fasting has one pillar, which is worshipping Allah (Mighty and Majestic) by abstaining from the things that break the fast from the rising of the dawn until the setting of the sun. The dawn referred to here is the second dawn, not the first. The second dawn is distinguished from the first by three characteristics.
The first is that the second dawn appears horizontally across the horizon, while the first dawn is vertical, meaning it extends from the east to the west. As for the second dawn, it extends from the north to the south. The second characteristic is that there is no darkness after the second dawn; rather, the light continues to increase until the sun rises. As for the first dawn, it is followed by darkness after its ray appears.
The third distinguishing feature is that the whiteness of the second dawn is connected to the horizon, whereas there is darkness between the first dawn and the horizon. The first dawn has no ruling in the Shari'ah; the Fajr prayer is not valid with it, and it does not prohibit food for the fasting person, unlike the second dawn.