All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It is permissible for you to sleep while you are in a state of major impurity. But it is recommended for you to perform ablution before you sleep. 'Aa'ishah narrated that when the Prophet was in a state of major impurity, he used to wash his private parts and perform ablution as if for the prayer. [Al-Bukhari and Muslim] So, it is disliked for a person in major impurity to sleep without having performed ablution. This is the ruling on someone who is in a state of major impurity, and there is no difference between the one who legally was in this state, and the one who was illegally in this state. A Muslim is obliged to fear Allaah and avoid His Prohibitions. He should also seek forgiveness for his sins. The angel of death could take his soul while he is persisting in sin, and so, he will meet Allaah while having disobeyed him, and without regretting or having sought forgiveness for his sin. Therefore, he will deserve the punishment of disobedient people and the threat of sinners.
We ask Allaah to enable us to do good and guide us to the straight path. Allaah Knows best.