Quran 14:31

قُل لِّعِبَادِىَ ٱلَّذِينَ ءَامَنُواْ يُقِيمُواْ ٱلصَّلَوٰةَ وَيُنفِقُواْ مِمَّا رَزَقۡنَـٰهُمۡ سِرًّ۬ا وَعَلَانِيَةً۬ مِّن قَبۡلِ أَن يَأۡتِىَ يَوۡمٌ۬ لَّا بَيۡعٌ۬ فِيهِ وَلَا خِلَـٰلٌ ٣١

Exhort My servants who believed to observe the Salat (Contact Prayer), and to give (to charity) from our provisions to them, secretly and publicly, before a day comes where there is neither trade, nor nepotism.