The claim
Critics argue that calling the earth a "resting place" (mihād) spread out and pinned by mountains shows the Qur'an teaches a flat earth.
The kernel of concern
The kernel is fair: the words mihād (a spread-out bed) and the image of the earth being "spread" do, on a surface reading, evoke a flat expanse, and some pre-modern peoples did hold flat-earth cosmologies.
What the verse actually says
The verse says, "Have We not made the earth a resting place" (78:6) — it describes the earth's function as habitable and stable for human life, not its geometric shape. The vocabulary of spreading and settling is about livability, comfort, and provision, paralleling how a bed or cradle is prepared.
The honest position
The honest position is that these verses are phenomenological and functional, describing how the earth serves humanity, not asserting a cosmological model of its shape. The Qur'an's aim is to evoke gratitude and infer God's power to resurrect.
Strongest counter-arguments
A locally flat-seeming surface is exactly how the ground appears and functions to people walking on it, so the language fits everyday experience regardless of global shape. Many classical Muslim scholars (such as Ibn Ḥazm and al-Rāzī) affirmed the earth's sphericity and saw no conflict, reading "spreading" as preparing the surface for habitation. Other verses describe God "wrapping" night over day (39:5), language that some scholars connected to a curved, rotating earth, showing the text does not commit to flatness.