وَأَخي هارونُ هُوَ أَفصَحُ مِنّي لِسانًا فَأَرسِلهُ مَعِيَ رِدءًا يُصَدِّقُني ۖ إِنّي أَخافُ أَن يُكَذِّبونِ

And my brother Aaron is more fluent than me in tongue, so send him with me as support, verifying me. Indeed, I fear that they will deny me."