What is zakat?

خُذۡ مِنۡ أَمۡوَٰلِهِمۡ صَدَقَةٗ تُطَهِّرُهُمۡ وَتُزَكِّيهِم بِهَا وَصَلِّ عَلَيۡهِمۡۖ إِنَّ صَلَوٰتَكَ سَكَنٞ لَّهُمۡۗ وَٱللَّهُ سَمِيعٌ عَلِيمٌ ﴿١٠٣﴾

Take, [O Muḥammad], from their wealth a charity by which you purify them and cause them increase, and invoke [Allāh's blessings] upon them. Indeed, your invocations are reassurance for them. And Allāh is Hearing and Knowing.

إِنَّ ٱلَّذِينَ ءَامَنُواْ وَعَمِلُواْ ٱلصَّٰلِحَٰتِ وَأَقَامُواْ ٱلصَّلَوٰةَ وَءَاتَوُاْ ٱلزَّكَوٰةَ لَهُمۡ أَجۡرُهُمۡ عِندَ رَبِّهِمۡ وَلَا خَوۡفٌ عَلَيۡهِمۡ وَلَا هُمۡ يَحۡزَنُونَ ﴿٢٧٧﴾

Indeed, those who believe and do righteous deeds and establish prayer and give zakāh will have their reward with their Lord, and there will be no fear concerning them, nor will they grieve.

۞ إِنَّمَا ٱلصَّدَقَٰتُ لِلۡفُقَرَآءِ وَٱلۡمَسَٰكِينِ وَٱلۡعَٰمِلِينَ عَلَيۡهَا وَٱلۡمُؤَلَّفَةِ قُلُوبُهُمۡ وَفِي ٱلرِّقَابِ وَٱلۡغَٰرِمِينَ وَفِي سَبِيلِ ٱللَّهِ وَٱبۡنِ ٱلسَّبِيلِۖ فَرِيضَةٗ مِّنَ ٱللَّهِۗ وَٱللَّهُ عَلِيمٌ حَكِيمٞ ﴿٦٠﴾

Zakāh expenditures are only for the poor and for the needy and for those employed for it and for bringing hearts together [for Islām] and for freeing captives [or slaves] and for those in debt and for the cause of Allāh and for the [stranded] traveler - an obligation [imposed] by Allāh. And Allāh is Knowing and Wise.