Allah consoles His Prophet Muhammad ﷺ for the disbelief of his people and gives him the glad tidings of good consequences and victory in this world and the Hereafter, as happened to Musa bin `Imran, peace be upon him, whom Allah sent with clear proof and definitive evidence. Allah says:
بِـَايَـتِنَا وَسُلْطَانٍ مُّبِينٍ
(with Our Ayat, and a manifest authority). Authority means proof and evidence.
إِلَى فِرْعَوْنَ
(to Fir`awn), who was the king of the Copts of Egypt.
وَهَـمَـنَ
(Haman) who was his adviser.
وَقَـشرُونَ
(and Qarun) who was the richest trader among the people of his time.
Frequent references were made earlier in the text to the warnings given to deniers of pure monotheism and prophethood which brought more opposition and hostility from disbelievers. Naturally, this situation made the Holy Prophet ﷺ sad. It was to comfort him that, in nearly two sections cited above, mentioned there is the story of Sayyidna Musa (علیہ السلام) and Pharaoh. In this story, there is a lengthy dialogue between the Pharaoh, his people and a righteous elder who, despite being a scion of the House of the Pharaoh, had believed in the faith of Sayyidna Musa (علیہ السلام) after having seen the miracles shown at his hands - but, had kept his faith secret until that time. Once this dialogue took place, his faith stood declared automatically and conclusively.
‘He may cause you to change your religion’ here means that he might change the form of religion which had come down to them from their ancestors, so that a new religion might prevail among the people. Pharaoh expressed his intention of slaying Moses, otherwise he might find supporters among the people of his community and, with their help, try to create unrest (fasad)in the country; he wanted him to be killed at the very outset. The greatest impediment to the acceptance of Truth is man’s overweening pride. In order to elevate himself, he wants to lower the Truth. But the supreme supporter of Truth is God, the Lord of the Universe. In the beginning, the opponents of Truth may apparently suppress it, but God’s support guarantees that finally it will be the Truth which will prevail.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.