Surah Al-Qasas (28:34)

وَأَخِى هَٰرُونُ هُوَ أَفْصَحُ مِنِّى لِسَانًا فَأَرْسِلْهُ مَعِىَ رِدْءًا يُصَدِّقُنِىٓ إِنِّىٓ أَخَافُ أَن يُكَذِّبُونِ

And my brother, Aaron—he is clearer than I in tongue; so send him with me as a support, confirming me. Indeed, I fear that they will deny me.