Perform wudhu before sleeping when you are junub.

This hadith explains the importance of performing wudu’ before going to sleep when one is in a state of ritual impurity. It was narrated from ‘Abdullah bin ‘Umar that ‘Umar said to the Prophet Muhammad (peace be upon him): "O Messenger of Allah! May any one of us sleep while he is Junub?" The Prophet Muhammad replied that it is permissible for someone to sleep while they are junub as long as they perform wudu’ first. This hadith teaches us that we should always strive to maintain cleanliness and purity in our lives by performing wudu’ regularly. It also reminds us that we should not neglect our religious obligations even if we are tired or busy with other activities.