مَا كَانَ لِلَّهِ أَن يَتَّخِذَ مِن وَلَدٍ سُبْحَانَهُ
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It befits not (the majesty of) Allah that He should beget a son. Glorified be He.
Means glory be unto Him, He is far exalted above that which these ignorant, wrongdoing, transgressing people say about Him.
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إِذَا قَضَى أَمْرًا فَإِنَّمَا يَقُولُ لَهُ كُن فَيَكُونُ
When He decrees a thing, He only says to it: "Be!" -- and it is.
Whenever He wants something, He merely commands it and it happens as He wills.
This is as Allah says,
إِنَّ مَثَلَ عِيسَى عِندَ اللَّهِ كَمَثَلِ ءَادَمَ خَلَقَهُ مِن تُرَابٍ ثُمَّ قَالَ لَهُ كُن فَيَكُونُ
الْحَقُّ مِن رَّبِّكَ فَلَ تَكُنْ مِّن الْمُمْتَرِينَ
Verily, the likeness of `Isa before Allah is the likeness of Adam. He created him from dust, then said to him: "Be" -- and he was. (This is) the truth from your Lord, so be not of those who doubt. (3:59-60)
`Isa commanded the Worship of Allah Alone, then the People differed after Him
Allah said;
وَإِنَّ اللَّهَ رَبِّي وَرَبُّكُمْ فَاعْبُدُوهُ هَذَا صِرَاطٌ مُّسْتَقِيمٌ