Ar-Ra'd 13:43

Wayaqoolu allatheena kafaroo lastamursalan qul kafa billahi shaheedan bayneewabaynakum waman AAindahu AAilmu alkitab

And those who have disbelieved say, "You are not a messenger." Say, [O Muḥammad], "Sufficient is Allāh as Witness between me and you, and [the witness of] whoever has knowledge of the Scripture."

The disbelievers say, “You are not a messenger.” Say, “Allah is sufficient as a witness between me and you, and those too (are my witnesses) who have the knowledge of the Book.”