وَجَعَلْنَا السَّمَاء سَقْفًا مَّحْفُوظًا ...

And We have made the heaven a roof, safe and well-guarded.

means, covering the earth like a dome above it.

This is like the Ayah,

وَالسَّمَآءَ بَنَيْنَـهَا بِأَيْدٍ وَإِنَّا لَمُوسِعُونَ

With Hands We constructed the heaven. Verily, We are able to extend the vastness of space thereof. (51:47)

وَالسَّمَآءِ وَمَا بَنَـهَا

By the heaven and Him Who built it. (91:5)

أَفَلَمْ يَنظُرُواْ إِلَى السَّمَآءِ فَوْقَهُمْ كَيْفَ بَنَيْنَـهَا وَزَيَّنَّـهَا وَمَا لَهَا مِن فُرُوجٍ

Have they not looked at the heaven above them, how We have made it and adorned it, and there are no rifts in it. (50:6)

The building and making described here refers to the raising of the dome, as when the Messenger of Allah said,

بُنِيَ الْإِسْلَامُ عَلَى خَمْس

Islam is built on five.

i.e., five pillars, which can only refer to a tent as familiar among the Arabs.

...مَّحْفُوظًا ...

safe and well-guarded.

means, high and protected from anything reaching it.

Mujahid said,

"Raised up.''

... وَهُمْ عَنْ آيَاتِهَا مُعْرِضُونَ ﴿٣٢﴾

Yet they turn away from its signs.

This is like the Ayah:

وَكَأَيِّن مِّن ءَايَةٍ فِى السَّمَـوَتِ وَالاٌّرْضِ يَمُرُّونَ عَلَيْهَا وَهُمْ عَنْهَا مُعْرِضُونَ

And how many a sign in the heavens and the earth they pass by, while they are averse therefrom. (12:105)

They do not think about how Allah has created it, so vast and high, and adorned it with heavenly bodies both stationary and moving by night and day, such as the sun which completes its circuit in one day and night, until it completes its allotted time, which no one knows except Allah, Who created it and subjugated it and directed its course.

Then Allah says, drawing attention to some of His signs,