Manking had already winessed " La Ilaha Illa Allah"

[Al-fateh]

English Yusuf Ali: [7:172]
When thy Lord drew forth from the Children of Adam - from their loins - their descendants, and made them testify concerning themselves, (saying): "Am I not your Lord (who cherishes and sustains you)?"- They said: "Yea! We do testify!" (This), lest ye should say on the Day of Judgment: "Of this we were never mindful":