Tafsir of Al-Isra 17:15

{Whoever is guided is only guided for [the benefit of] his soul. And whoever errs only errs against it. And no bearer of burdens will bear the burden of another. And never would We punish until We sent a messenger.}

Meaning: Every soul that bears a burden only carries its own burden, not the burden of another soul.

{And never would We punish}: It is not consistent with Our correctness—a correctness to which wisdom calls—that We should punish a people until We have sent a messenger to them, thereby establishing the proof against them.

If you ask: The proof is already binding upon them before the sending of messengers, because they possess the rational evidences by which God is known. They have neglected to reflect, despite being capable of it, and they deserve punishment for neglecting to reflect upon what they possess and for their disbelief therein—not for neglecting the religious laws, which cannot be known except through divine revelation, and the practice of which is not valid except after faith.

I reply: The sending of messengers is part of the process of alerting [people] to reflect and awakening them from the slumber of heedlessness, so that they may not say: "We were heedless; if only You had sent a messenger to us to alert us to reflect upon the rational evidences."

{And when We intend to destroy a city, We command its affluent but they defiantly disobey therein; so the word comes into effect upon it, and We destroy it with [complete] destruction.}