وَمَاذَا عَلَيْهِمْ لَوْ اٰمَنُوْا بِاللّٰهِ وَالْيَوْمِ الْاٰخِرِ وَاَنْفَقُوْا مِمَّا رَزَقَهُمُ اللّٰهُ ۗوَكَانَ اللّٰهُ بِهِمْ عَلِيْمًا ( النساء: ٣٩ )
Wa maazaa 'alaihim law aamanoo billaahi wal Yawmil Aakhiri wa anfaqoo mimmaa razaqahumul laah; wa kaanallaahu bihim Aaleemaa (an-Nisāʾ 4:39)
And what [harm would come] upon them if they believed in Allah and the Last Day and spent out of what Allah provided for them? And Allah is ever, about them, Knowing. (An-Nisa  : 39)
1 Mufti Taqi Usmani
What harm was there for them if they had believed in Allah and the Last Day, and spent out of what Allah had given them. Allah knows all about them.