Formal prayer (Salat, Salah) is the second pillar of Islam, and most important of a Muslims acts of worship. Prophet Muhammed Said "The first of one's actions for which a slave of Allah will be held accountable on the day of jedgement will be one's prayers. If they are correct and accounted for, then he or she will have succeeded gained Paradise, and if they are lacking, then he or she will have failed lost paradise. If there is something defective in his or her obligatory prayers, then Allah will say, see if my slave has any supererogatory prayers with which that which was defective in his or her obligatory prayers may be completed. Then the rest of his or her deeds will be judged in like manner."
(Reported in Ath Tirmidhi and others)
Author: Shaykh Mashhur Hasan Salman