434. What are Illiyeen and Sijjin? 

Verses (83:8, 83:19) of the Quran talk about two records that are maintained, known as Illiyeen and Sijjin.

The souls of the dead are immediately carried upwards into the world above.

The souls of the virtuous are carried upwards and registered in the Illiyeen, then brought back to earth, for questioning in the grave, this takes place in seconds. Prophet Muhammad said when the soul of an evil person is carried above to the Lord, He orders it to be taken to the depths of the earth and get it registered there in the book known as Sijjin.

Please refer to point no;177 to know more details about this subject.