Tafsir of Al-Isra 17:49

"And they said, 'When we have become...'"

When they said, "When we have become bones," it was said to them: {Say, "Be stones or iron."}

The command "Be" (kūnū) is a response to their statement "We have become" (kunnā). It is as if it were said: "Be stones or iron, and do not be bones," for He is capable of bringing you to life.

The meaning is: You deem it unlikely that Allah will renew your creation and return you to the state of life, moisture, and freshness after you have become dry bones—even though bones are a part of a living being, indeed, the pillar of its creation upon which the rest is built. It is not strange for Allah, by His power, to return them to their original state.

However, even if you were the furthest things from life and the moisture of the living—of a nature from which humans are not composed—such as being hard stones or iron, despite their inherent rigidity and hardness, He would still be capable of returning you to the state of life.

{Or [some other] creation that is even greater in your breasts} Meaning: Or a creation that you deem even more impossible to accept life, and which you consider too great for the Creator to bring to life; He will surely bring it to life.

It is also said: What is "greater in their breasts" is death. It is also said: The heavens and the earth.

{They will shake their heads at you} Meaning: They will move them toward you in astonishment and mockery.

{On the Day He will call you and you will respond with His praise, and you will think that you had not remained [in the world] except for a little while.}