Huraith Ibn Qabisa reported: The Prophet, peace be upon him, said: Allah Almighty says:
The first actions for which a servant of Allah will be held accountable on the Day of Resurrection will be his prayers. If they are in order, then he will have prospered and succeeded; but if they are lacking, then he will have failed and lost. If there is something defective in his obligatory prayers then the Lord the Exalted will say: see if My servant has any extra prayers which can complete what is defective in his obligatory prayers. Then the rest of his actions will be judged in the same way.
[Sunan At-Tirmidhi, Book of Prayer, Number 413]