First thing to be accounted

Abdullah b. Qart رضي الله عنه narrated Prophet ﷺ said [meaning]: The first thing to be accounted for on the Day of Judgment will be prayer. If it is proved correct all his deeds will be correct and if it is proved wrong, all his deeds will be void. Tibrani, Al Targhib wal Tarhib. P. 143, Vol 1.