5:18
وَقَالَتِ ٱلْيَهُودُ وَٱلنَّصَٰرَىٰ نَحْنُ أَبْنَٰٓؤُا۟ ٱللَّهِ وَأَحِبَّٰٓؤُهُۥ ۚ قُلْ فَلِمَ يُعَذِّبُكُم بِذُنُوبِكُم ۖ بَلْ أَنتُم بَشَرٌۭ مِّمَّنْ خَلَقَ ۚ يَغْفِرُ لِمَن يَشَآءُ وَيُعَذِّبُ مَن يَشَآءُ ۚ وَلِلَّهِ مُلْكُ ٱلسَّمَٰوَٰتِ وَٱلْأَرْضِ وَمَا بَيْنَهُمَا ۖ وَإِلَيْهِ ٱلْمَصِيرُ
But the Jews and the Christians say, "We are the children of Allah and His beloved." Say, "Then why does He punish you for your sins?" Rather, you are human beings from among those He has created. He forgives whom He wills, and He punishes whom He wills. And to Allah belongs the dominion of the heavens and the earth and whatever is between them, and to Him is the [final] destination.
Translation · Saheeh International
Tafsir
Ibn Kathīr (abridged)
The Polytheism and Disbelief of the Christians
Allah states that the Christians are disbelievers because of their claim that `Isa, son of Maryam, one of Allah's servants and creatures, is Allah. Allah is holier than what they attribute to Him. Allah then reminds them of His perfect ability over everything and that everything is under His complete control and power,
قُلْ فَمَن يَمْلِكُ مِنَ اللَّهِ شَيْئاً إِنْ أَرَادَ أَن يُهْلِكَ الْمَسِيحَ ابْنَ مَرْيَمَ وَأُمَّهُ وَمَن فِى الاٌّرْضِ جَمِيعاً
(Say: "Who then has the least power against Allah, if He were to destroy the Messiah, son of Maryam, his mother, and all those who are on the earth together") Therefore, if Allah wills to do that, who would be able to stop Him or prevent Him from doing it Allah then said,
وَللَّهِ مُلْكُ السَّمَـوَتِ وَالاٌّرْضِ وَمَا بَيْنَهُمَا يَخْلُقُ مَا يَشَآءُ
(And to Allah belongs the dominion of the heavens and the earth, and all that is between them. He creates what He wills.) All things in existence are Allah's property and creation and He is able to do everything. He is never asked about what He does with His power, domain, justice and greatness so this refutes the Christian creed, may Allah's continued curses be upon them until the Day of Resurrection.