Tafsir of Az-Zukhruf 43:6-7

"And how many a prophet did We send among the former peoples." (6)

"And there came not to them any prophet except that they used to mock him." (7)

This is a confirmation of what preceded it, by explaining that the extravagance of the former nations did not prevent Him, the Exalted, from sending prophets to them, and it serves as a consolation to the Messenger of Allah (may Allah bless him and grant him peace) regarding the mockery of his people toward him (upon him be peace). Indeed, it has been said: "When a calamity becomes widespread, it becomes easier to bear."

Kam (how many) is the object of arsalna (We sent), and fi al-awwalin (among the former peoples) is related to it, or it is an adjective for nabi (prophet). Wa ma ya'tihim (And there came not to them...) is for continuity, and its pronoun refers to the "former peoples."