إِنَّما يَتَقَبَّلُ اللَّهُ مِنَ المُتَّقينَ
*"Indeed, Allaah only accepts from the righteous [who fear Him].* [5:27]
Ibn 'Awn said, 'Do not feel secure because of a great number of deeds for you do not know if they have been accepted or not. Do not feel secure about your sins for you do not know if they have been expiated or not. This is because all of your deeds are unseen to you and you have no idea what Allaah will do with them.'
one of the Companions was overcome with anxiety at the time of his death and he was asked after his state to which he replied, "Allaah took His creatioin in two handfuls, a handful for Paradise and a handful for Hell, and I have no idea to which handful I belong." [Musnad Ahmad #17594]
Taken from: The Journey to Allaah by Ibn Rajab al-Hanbali