The Women
وَلَوْ أَنَّا كَتَبْنَا عَلَيْهِمْ أَنِ ٱقْتُلُوٓا۟ أَنفُسَكُمْ أَوِ ٱخْرُجُوا۟ مِن دِيَـٰرِكُم مَّا فَعَلُوهُ إِلَّا قَلِيلٌ مِّنْهُمْ ۖ وَلَوْ أَنَّهُمْ فَعَلُوا۟ مَا يُوعَظُونَ بِهِۦ لَكَانَ خَيْرًا لَّهُمْ وَأَشَدَّ تَثْبِيتًا
And if We had decreed upon them, "Kill yourselves" or "Leave your homes," they would not have done it, except for a few of them. But if they had done what they were instructed, it would have been better for them and a firmer position [for them in faith].
Nearby ayahs help place verse 4:66 in sequence and meaning.
وَمَآ أَرْسَلْنَا مِن رَّسُولٍ إِلَّا لِيُطَاعَ بِإِذْنِ ٱللَّهِ ۚ وَلَوْ أَنَّهُمْ إِذ ظَّلَمُوٓا۟ أَنفُسَهُمْ جَآءُوكَ فَٱسْتَغْفَرُوا۟ ٱللَّهَ وَٱسْتَغْفَرَ لَهُمُ ٱلرَّسُولُ لَوَجَدُوا۟ ٱللَّهَ تَوَّابًا رَّحِيمًا
And We did not send any messenger except to be obeyed by permission of Allah. And if, when they wronged themselves, they had come to you, [O Muhammad], and asked forgiveness of Allah and the Messenger had asked forgiveness for them, they would have found Allah Accepting of repentance and Merciful.
فَلَا وَرَبِّكَ لَا يُؤْمِنُونَ حَتَّىٰ يُحَكِّمُوكَ فِيمَا شَجَرَ بَيْنَهُمْ ثُمَّ لَا يَجِدُوا۟ فِىٓ أَنفُسِهِمْ حَرَجًا مِّمَّا قَضَيْتَ وَيُسَلِّمُوا۟ تَسْلِيمًا
But no, by your Lord, they will not [truly] believe until they make you, [O Muhammad], judge concerning that over which they dispute among themselves and then find within themselves no discomfort from what you have judged and submit in [full, willing] submission.
وَإِذًا لَّـَٔاتَيْنَـٰهُم مِّن لَّدُنَّآ أَجْرًا عَظِيمًا
And then We would have given them from Us a great reward.
وَلَهَدَيْنَـٰهُمْ صِرَٰطًا مُّسْتَقِيمًا
And We would have guided them to a straight path.