(It will be said to him);"Read your Book. You yourself are sufficient as a reckoner against you this Day."
meaning, you have not been treated unjustly and nothing has been recorded against you except what you have done, because you remember everything that you have done, and no one will forget anything that he did. Everyone will be able to read his Book, whether he is literate or illiterate.
أَلْزَمْنَاهُ طَأيِرَهُ فِي عُنُقِهِ
And We have fastened every man's Ta'irah (deeds) to his neck,
The neck is mentioned because it is a part of the body that has no counterpart, and when one is restrained by it, he has no escape.
Ma`mar narrated from Qatadah,
"His deeds,
وَنُخْرِجُ لَهُ يَوْمَ الْقِيَامَةِ
(and on the Day of Resurrection, We shall bring out for him), We shall bring forth those deeds."
كِتَابًا يَلْقَاهُ مَنشُورًا
(a Book which he will find wide open).
Ma`mar said;Al-Hasan recited,
عَنِ الْيَمِينِ وَعَنِ الشِّمَالِ قَعِيدٌ
one sitting on the right and one on the left. (50;17)
And he said;
"O son of Adam, your Book has been opened for you, and two noble angels have been entrusted to accompany you, one on your right and one on your left.
The one who is on your right records your good deeds, and the one who is on your left records your bad deeds. `So do whatever you want, a lot or a little, until you die, then I will fold up your Book and tie it to your neck with you in your grave. Then when you come out on the Day of Resurrection, you will find the Book wide open, so read your Book.'
By Allah, the One Who makes you accountable for your own deeds is being perfectly just."
These are some of the best words Al-Hasan ever spoke, may Allah have mercy on him