Sura al-Aḥzāb 33:38

مَّا كَانَ عَلَى ٱلنَّبِىِّ مِنْ حَرَجٍ فِيمَا فَرَضَ ٱللَّـهُ لَهُۥ سُنَّةَ ٱللَّـهِ فِى ٱلَّذِينَ خَلَوْا۟ مِن قَبْلُ وَكَانَ أَمْرُ ٱللَّـهِ قَدَرًا مَّقْدُورًا

mā kāna ʿalā l-nabiyyi min ḥarajin fī-mā faraḍa allāhu lahu sunnata allāhi fī lladhīna khalaw min qablu wa-kāna amru allāhi qadaran maqdūran

There can be no difficulty to the Prophet in what Allah has indicated to him as a duty. It was the practice (approved) of Allah amongst those of old that have passed away. And the command of Allah is a decree determined.