Tafsir of Ash-Shu`ara' 26:16

And go both of you to Fir`awn, and say: `We are the Messengers of the Lord of the all that exists.' This is like the Ayah,

إنا رسوﻻ ربك

Verily, we are both Messengers of your Lord. (20:47) which means, `both of us have been sent to you,'

أن أرسل معنا بني إسراييل