Tafsir of Al-An'am 6:96

(The Splitter of the dawn) is a predicate for an omitted subject—meaning, "He is the Splitter"—or it is another predicate. (The dawn)—with a kasra on the hamza—is a verbal noun (masdar) used to denote the morning (al-subh). Imru’ al-Qais said: O long night, will you not clear away with morning? Yet the morning is no better than you. Al-Hasan recited it with a fatha, treating it as the plural of subh, like qufl and aqfal. He cited the verse: He annihilated Riyāh and the sons of Riyāh; the passing of the evenings and the mornings... where al-masa’ (evening) and al-isbah (morning) are used—with both kasra and fatha—as verbal nouns and as the plurals of masa’ and subh. The "Splitter" (faliq) is the "Creator" (khaliq), according to what is narrated from Ibn Abbas (may Allah be pleased with him), Qatadah, and al-Dahhak. Many others have said it means "the cleaver" (al-shaqq).

This is considered problematic, as the apparent reality is that it is the darkness that splits to reveal the morning. The response given is that there are two types of dawn: the "true" dawn (sadiq), which is light spreading horizontally across the horizon, and the "false" dawn (kadhib), which appears vertically, with its top being brighter than its base, only to be followed by darkness. Regarding the former, it means the splitting of the morning light from the day; or, it may be said that there is an implied addition in the speech, meaning: "The Splitter of the darkness of the morning by the morning." This is because the horizon from the western and southern sides is filled with darkness, and the light only appears in the eastern side, as if the horizon were a sea filled with darkness, and He—the Exalted—cleaved that dark sea by running a stream of light through it. Regarding the latter, it means He—the Exalted—split it from the darkness of the late night.

What has been mentioned regarding the division of the dawn into "true" and "false" is attested to by observation, and no two people would dispute it. However, there is discourse among the astronomers regarding its cause. In essence, the dawn—as well as the twilight—is an illumination within the "vapor sphere" due to the sun approaching the eastern horizon and moving away from the western one. It has been verified that the vapor sphere is condensed air containing terrestrial and aquatic particles that have ascended from their respective spheres due to the heat of the sun and other factors. This air takes the shape of a sphere surrounding the Earth, centered upon it, with a surface parallel to its surface, having a maximum height from the Earth's center in all directions (which necessitates its sphericity). It is of varying density, for what is closer to the Earth is denser than what is further away, as the more subtle rises and moves further than the denser—yet the condensation does not reach the point of obscuring what is behind it. This sphere terminates at a limit it does not exceed, which is approximately fifty-one miles from the Earth's surface.

The Earth casts a shadow in the form of a cone; its base is a circle upon the Earth that is almost a great circle facing the sun, with its apex opposite the sun. The Earth is divided by this base into two parts: a larger, illuminated part facing the sun, and a dark part opposite it. Light and darkness move across the surface of the Earth in a single day and night cycle like two opposing standards, one white and one black. The sun's rays encompass the shadow cone from all sides and are diffused throughout all the spheres, except for a small portion of the moon's sphere and Mercury's sphere that fall within the Earth's shadow cone. However, the spheres, being extremely luminous, allow the rays to pass through them without reflecting them, and thus we do not see them as illuminated. Likewise, the clear air surrounding the vapor sphere does not accept light.

As for the vapor sphere, it is of varying density, as what is closer to the Earth is denser than what is further, and the denser is more receptive to illumination. Therefore, the dense, rough material, through the mixing of many forms from the surface of the shadow cone, is receptive to light. Day is the duration of this cone being below the horizon, and night is the duration of it being above it. Once all of this is established, it is said: when the sun’s proximity to the eastern horizon increases, the cone's inclination towards the west increases, and it continues this way until the ray encompassing it is seen. The first thing seen is that which is closest to the observer’s position—a line extending from his sight along the surface of a vertical circle passing through the sun's center, perpendicular to the line tangent to the sun and the Earth. This is the line on the shared intersection between the ray and the shadow. Thus, the light is seen first, elevated above the horizon at the location of the perpendicular, elongated like a straight line, while the space between it and the horizon appears dark due to its distance, even if it is actually illuminated. The density of the air near the horizon has a role in this; this is the false dawn.

Then, when it approaches the eastern horizon, the light is seen horizontally and spread out, increasing moment by moment, and the first [light] is erased by this strong radiance, just as the light of torches and stars is erased by the light of the sun; thus, one imagines that the first has vanished. This is the true dawn.

[...Detailed technical/astronomical discussion follows regarding the geometry of the shadow cone, the positions of the sun, and the opinions of various scholars including al-Razi, Ibn al-Haytham, and al-Qarafi...]

(And He made the night a rest)—meaning, those who are tired during the day take rest in it, and find comfort in it because of their relaxation therein. Everything one finds comfort in and feels at ease with—such as a spouse or a beloved—is called a sakan (rest/tranquility). From this, fire is called sakan because one finds comfort in it; that is why they named it mu’nisa (the comforting one). Ibn Abi Hatim narrated from Qatadah that the meaning is that every bird and beast rests in it. A similar report is narrated from Ibn Abbas and Mujahid. The meaning then is "made the night to be rested in," derived from sukun (quietude and stability), as in His saying: (that you may rest therein).

(And the sun and the moon for reckoning)—meaning, according to different cycles by which the times for acts of worship and transactions are measured; or "calculated for reckoning." Husban (with a damma) is the verbal noun of hasaba (with a fatha), just as hisban (with a kasra) is the verbal noun of hasiba (with a kasra); the latter is the primary form heard in such contexts, while the former is considered irregular.

(That is the determination of the Exalted)—meaning, the Almighty, the Conqueror, to Whom nothing is difficult among all things, including the regulation of these two according to a specific way. (The All-Knowing)—the One who is Excessive in knowledge of all known things, including the worldly and afterlife benefits contained within that determination.