http://sharingknowledgeofislam.blogspot.com/2009/04/errors-in-prayers-that-must-be-avoided.html

Source Ad-Deen an-Naseehah


Salat (namaaz) or prayer is one of the most important pillars of Islam. The Messenger of Allah (sallallaahu 'alaihi wasallam) warned that the first thing man will be questioned about on the Day of Resurrection is prayer. Abu Hurairah said, "I heard the Messenger of Allah (sallallaahu 'alaihi wasallam) saying:

The first act of worship man shall be questioned about on the Day of Resurrection is prayer. If it was performed correctly1, man shall certainly succeed and prosper, if it is not, he shall certainly lose and fail. If, however, man's prayer was incomplete, the Lord, the Exalted, would say (to His Angels), "See if my slave performed supererogatory (nafl) prayers to make up what he had missed of the obligatory prayers. The rest of man's deeds will be reckoned in the same manner2.