﴿ وَقَالَ مُوسَىٰ يَٰفِرْعَوْنُ إِنِّى رَسُولٌۭ مِّن رَّبِّ ٱلْعَٰلَمِينَ ﴾

“And Moses said: "O Pharaoh! Verily, I am an apostle from the Sustainer of all the worlds,”

The verse is a clear declaration of the prophet Musa (علیہ السلام) before Pharaoh that he was a messenger of Allah, the Lord of all the worlds, and that his status of prophethood does not allow him to ascribe anything but truth to Allah because the message given to the prophets by Allah is a sacred trust and it is a great sin to tamper with it. All the prophets of Allah are free of all sins and cannot do so. The prophet Musa (علیہ السلام) tried to convince them that they should believe him because his truthfulness was beyond question and that he had never uttered a word of lie. In addition to this, his miracles are a clear proof to support his claim to prophethood.