Quran 28:34 from Surah Al-Qasas on Divine Marvels.
وَأَخِي هَٰرُونُ هُوَ أَفۡصَحُ مِنِّي لِسَانٗا فَأَرۡسِلۡهُ مَعِيَ رِدۡءٗا يُصَدِّقُنِيٓۖ إِنِّيٓ أَخَافُ أَن يُكَذِّبُونِ
English translation: And my brother Harun he (is) more eloquent than me (in) speech so send him with me (as) a helper who will confirm me Indeed I fear that they will deny me
Transliteration: wa-akhi harunu huwa afsahu minni lisanan fa-arsil'hu ma'iya rid'an yusaddiquni inni akhafu an yukadhibuni