Tafsir of Al-Mulk 67:17

"Or have you felt secure in Him Who is in the heaven that He should send against you a storm of stones?"

This is a shift from the previous threat to another form of threat. It means: "Nay, have you felt secure in Him Who is in the heaven that He should send against you [a storm of stones]?"

The discussion regarding the hasib (storm of stones) has preceded, and the threat of causing the earth to swallow them [mentioned previously] came first due to the relevance of mentioning the earth in His saying, "It is He Who has made the earth subservient for you." He mentioned the favor of facilitating movement upon its paths, then mentioned the sending of the storm of stones. This second [threat] stands in opposition to the favor mentioned in His saying, "and eat of His provision." Do you not see His saying, "And in the heaven is your provision"? This was stated in al-Kashshaf.

In Ghurrat al-Tanzil, al-Raghib states regarding why the threat of causing the earth to swallow them preceded the threat of the storm of stones: "Since the earth, which He, Glory be to Him, leveled for them for their stability so that they might worship their Creator upon it, was instead used by them to worship idols of wood or stone, they were threatened by that which is closest to them. The threat of the storm of stones from the heaven—which is the place of ascent for their good words and the paths of their righteous deeds—is because they exchanged these [virtues] for the evils of their disbelief and the hideousness of their deeds." Perhaps what was pointed to first [in the previous commentary] is more appropriate.

"Then you shall know how [My] warning is."

Meaning: "My warning." Nadhir is an infinitive, similar to its usage in the statement of Hassan: "So warn the likes of it, giving advice to Quraysh; for it is from the Most Merciful if they accept my warning."

It is appended to the ya pronoun. The reciters differ regarding it; some omit it during connection and affirm it during a pause, while others omit it in both states, considering the kasra sufficient. The meaning is: "You shall know the state of My warning and My ability to execute it when you witness that of which you were warned." However, knowledge at that time will not benefit you. It has also been recited, in a non-standard manner, as fasaya’lamun (they shall know) with the ya prefix.