The Conclusion of the Believer's Words, and the ultimate Destiny of both Parties
That believer said: `Why do I call you to salvation, which is the worship of Allah alone with no partner or associate, and belief in His Messenger, whom He has sent,'
(while you call me to the Fire! You invite me to disbelieve in Allah, and to join partners in worship with Him of which I have no knowledge;) means, on the basis of ignorance, with no proof or evidence.
وَأَنَاْ أَدْعُوكُمْ إِلَى الْعَزِيزِ الْغَفَّارِ
(and I invite you to the Almighty, the Oft-Forgiving!) means, with all His might and pride, He still forgives the sin of the one who repents to Him.
In verse 44, it was said: فَسَتَذْكُرُونَ مَا أَقُولُ لَكُمْ وَأُفَوِّضُ أَمْرِي إِلَى اللَّـهِ إِنَّ اللَّـهَ بَصِيرٌ بِالْعِبَادِ (Soon you will remember what I am saying to you. And I entrust my matter with Allah. Surely, Allah has all (His) servants in sight.). This is what the believer from the House of Pharaoh said at the end of his address to his people inviting them to accept the message of truth. Here, it was said that, should they not listen to him within that point of time, there would come a time when the punishment would seize them, and they would remember what he had told them. But, the remembrance of that particular time will be useless. And when by virtue of this lengthy dialogue, advice and invitation, the 'iman or faith of this believer from the House of Pharaoh stood disclosed before these people, he realized that they might bring some harm to him, therefore, he said that he was leaving his case to rest with Allah, for He is the guardian and protector of His servants. Early tafsir authority, Muqatil says: When the people of the Pharaoh, as he had apprehended, went after him, he escaped towards the mountains and they could not catch him.
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 41–45
In other words the sentence, ‘I call you towards the Lord of the Universe, whereas you call me towards one who is quite ineffectual both in this world and in the Hereafter.’ This presents the gist of the speech of a true believer. This gives an idea of what was being discussed in Pharaoh’s court. The discussion was on whether God or other man-made deities should be invoked. The true believer said that God is a living and dominant entity. Calling upon Him amounts to calling upon the real God. As opposed to this, he said that their deities were only the creation of their imagination or objects of superstition, and were of no avail either in this world or in the world Hereafter. When they (the deities) have no real existence, how can they confer any real advantage? (Tafsir ibn Kathir, vol. IV, p. 80).
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.