The Quran says that when the night and the day overlap, they make a ball (sphere):
[Quran 39.5] [Allah] Created the heavens and the Earth in truth. He overlaps [Yukawer in Arabic يُكَوِّرُ] the night over the day and overlaps [Yukawer يُكَوِّرُ] the day over the night, and enslaved the sun and the moon. ALL MOVE (Kullon Yajree كل يجري) to a prerecorded destiny. Is He not the Exalted, the Forgiver?
The Arabic word "Kura كرة" means ball; the Quran used its verb "Yukawer يُكَوِّرُ" meaning to make into a ball. The Quran says that the overlapping of the night and the day makes a ball (sphere).
How could an illiterate man who lived 1400 years ago have known that Earth is a sphere?
"ALL MOVE (Kullon Yajree كل يجري)" here the Quran is referring to ALL MOVING, not only the sun and moon but also Earth. In Arabic grammar there is difference between the singular (one), binary (two) and plural (three or more). The reference to binary is "Kulahuma Yajreean كلاهما يجريان" however the Quran said "Kullon yajree كل يجري" referring to the plural (three or more). Since the sun and moon are just two but the Quran refers to three or more then according to the Quran all the three move: sun, moon and Earth.
How could an illiterate man who lived 1400 years ago have known that all move sun, moon and Earth?
The Quran says that Earth has a diameter (diameter is simply twice the radius).
[Quran 55.33] O company of Jinn and man, escape the diameters (اقطار) of the Heavens and the Earth if you can, You won't escape without authority.
Diameter in Arabic is Kutr قطر. Its plural is Aktar اقطار. Radii and diameters are properties of circles or spheres only. This conforms with the previous verse, to make into a ball [Yukawer يُكَوِّرُ].
How could an illiterate man who lived 1400 years ago have known that Earth has a diameter?
"Sateh سطح" in Arabic means surface however this surface can have any shape. It could have the shape of a saddle:
This saddle shape is one type of "sateh سطح". It could have any shape but unfortunately "sateh سطح" was mistranslated to flat. Flat in Arabic is "musattah مسطح" however it was not used in the entire Quran.
[Quran 50.7] And the earth We have spread it out (والارض مددناها), and set thereon mountains standing firm, and have produced therein every kind of lovely pairs (of plants).
The Quran says that God spread out the Earth 'والارض مددناها' meaning increase in surface area during formation. 'Madda' in Arabic means 'spread out', however it was mistranslated to 'flat'.
The Quran says that God spread out Earth, that is, increased the surface area. Our solar system is 4.57 billion years old. Earth started accreting concurrently with the sun and our neighbouring planets 4.57 bln years ago. However during the accretion process the radius of Earth was not spontaneously 6400 km; but rather started a few kilometers long and progressively increased. But the surface area is a function of the radius (surface area = 4πR2), that is, as the radius increases the surface area increases. So the Quran correctly described the surface area as increasing. (This is contrary to the Bible where the creation of Earth was spontaneous.)
(The Bible says that Earth is a 2 dimensional flat disk and the heaven is like a canopy: Isaiah 40:22. And since Earth is flat then Jesus could see the entire Earth from a single high location Matthew 4:8)
Mistranslations: Quran 18.86 sun setting in a pond.