"And it was not for a messenger to bring a sign except by permission of Allah," meaning: until Allah permits him to do so. This is because they used to ask the Prophet (peace be upon him) to bring them a sign, and [it was known] that if the sign came and the people did not believe, Allah would destroy them.
He said: "And when the command of Allah comes," His decree, "it is judged with truth," meaning: Allah destroys them for their denial. "And there the falsifiers will lose," [when there comes to them] (fol. 306) the punishment. "The falsifiers" are the polytheists.
﴿وَمَا كَانَ لِرَسُولٍ أَنْ يَأْتِيَ بِآيَةٍ إِلَا بِإِذْنِ اللَّهِ﴾ أَي: حَتَّى يَأْذَن اللَّه لَهُ فِيهَا , وَذَلِكَ أَنهم كَانُوا يسْأَلُون النَّبي ﷺ أَن يَأْتِيهم بِآيَة وَأَن الْآيَة إِذا جَاءَت فَلم يُؤمن الْقَوْم أهلكهم اللَّه.
قَالَ: ﴿فَإِذَا جَاءَ أَمر الله﴾ قَضَاؤُهُ ﴿قضي بِالْحَقِّ﴾ أَي: أهلكهم اللَّه بتكذيبهم ﴿وَخَسِرَ هُنَالك المبطلون﴾ [حِين جَاءَهُم] (ل ٣٠٦) الْعَذَاب ﴿المبطلون﴾ الْمُشْركُونَ.