Tafsir of Nuh 71:27

إنك إن تذرهم يضلوا عبادك

If You leave them, they will mislead Your servants, meaning, `if You leave a single one of them they will lead your servants astray.' This refers to those whom He will create after them.

وﻻ يلدوا إﻻ فاجرا كفارا

and they will beget none but wicked disbelievers. meaning, wicked in their deeds and disbelieving in their hearts. He (Nuh) said this due to what he knew about them since he remained among them for nine hundred and fifty years. Then he said,