`Ali bin Abi Talhah reported that Ibn `Abbas said,

﴿وَمِمَّا رَزَقْنَـهُمْ يُنفِقُونَ﴾

(And spend out of what We have provided for them) means, "The Zakah due on their wealth.'' As-Suddi said that Abu Malik and Abu Salih narrated from Ibn `Abbas, as well as Murrah from Ibn Mas`ud and other Companions of the Messenger of Allah , that,

﴿وَمِمَّا رَزَقْنَـهُمْ يُنفِقُونَ﴾

(And spend out of what We have provided for them) means, "A man's spending on his family. This was before the obligation of Zakah was revealed.'' Juwaybir narrated from Ad-Dahhak, "General spending (in charity) was a means of drawing nearer to Allah, according to one's discretion and capability. Until the obligation of charity was revealed in the seven Ayat of Surat Bara'ah (chapter 9), were revealed. These abrogated the previous case.''

In many instances, Allah mentioned prayer and spending wealth together. Prayer is a right of Allah as well as a form of worshipping Him. It includes singling Him out for one's devotion, praising Him, glorifying Him, supplicating to Him, invoking Him, and it displays one's dependence upon Him. Spending is form of kindness towards creatures by giving them what will benefit them, and those people most deserving of this charity are the relatives, the wife, the servants and then the rest of the people. So all types of required charity and required spending are included in Allah's saying,

﴿وَمِمَّا رَزَقْنَـهُمْ يُنفِقُونَ﴾

(And spend out of what we have provided for them). The Two Sahihs recorded that Ibn `Umar said that the Messenger of Allah said,

«بُنِيَ الْإِسْلَامُ عَلَى خَمْسٍ: شَهَادَةِ أَنْ لَا إِلهَ إِلَّا اللهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللهِ، وَإِقَامِ الصَّلَاةِ، وَإِيتَاءِ الزَّكَاةِ، وَصَوْمِ رَمَضَانَ، وَحَجِّ الْبَيْت»

(Islam is built upon five (pillars): Testifying that there is no deity worthy of worship except Allah and that Muhammad is the Messenger of Allah, establishing the prayer, giving Zakah, fasting Ramadan and Hajj to the House.)

There are many other Hadiths on this subject.