An-Naba 78:12 - Linguistic Miracle

And created above you seven strong ones?

This is a very interesting word choice. شداد is translated as strong. At its root, it was

used for not only strengthening something, but also for tightening a knot. It implies firmness and solidity that is obtained as a result of tight binding of its particles; such as the knot tightly bound.⁹ This is important to note because later on, Allah will describe the heavens as being opened up on judgment day, which implies the breakage and untying of these knots.

The seven heavens, unlike the earth, are not soft. They are strong, intense and firm. We can dig the earth up and plant in it, but we cannot subjugate the heavens. We cannot dictate or alter its behaviour in any shape or form. Unlike the earth which is at our disposal, and generates food and all sorts of benefits for us, we cannot make the heavens budge even slightly.

⁹ Al-Muʿjam al-Ishtiqāqī al-Muʾaṣṣal li-Alfāẓ al-Qurʾān al-Karīm, vol. 2, p. 1114