The Quran

وَما كانَ لِمُؤمِنٍ وَلا مُؤمِنَةٍ إِذا قَضَى اللَّهُ وَرَسولُهُ أَمرًا أَن يَكونَ لَهُمُ الخِيَرَةُ مِن أَمرِهِم ۗ وَمَن يَعصِ اللَّهَ وَرَسولَهُ فَقَد ضَلَّ ضَلالًا مُبينًا

Muhammad Asad

Now whenever God and His Apostle have decided a matter¹, it is not for a believing man or a believing woman to claim freedom of choice insofar as they themselves are concerned:² for he who [thus] rebels against God and His Apostle has already, most obviously, gone astray.

I.e., whenever a specific law has been formulated as such in the Qur'an or in an injunction promulgated by the Prophet.
Lit., "to have a choice in their concern (min amrihim)" i.e., to let their attitude or course of action be determined, not by the relevant law, but by their personal interests or predilections.