Word by Word Analysis

وَمَا مَنَعَ ٱلنَّاسَ أَن يُؤْمِنُوٓا۟ إِذْ جَآءَهُمُ ٱلْهُدَىٰ وَيَسْتَغْفِرُوا۟ رَبَّهُمْ إِلَّآ أَن تَأْتِيَهُمْ سُنَّةُ ٱلْأَوَّلِينَ أَوْ يَأْتِيَهُمُ ٱلْعَذَابُ قُبُلًا 55

And nothing has prevented the people from believing when guidance came to them and from asking forgiveness of their Lord except that there [must] befall them the [accustomed] precedent of the former peoples or that the punishment should come [directly] before them.