It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Whoever falls asleep in the state of prostration, there is no ablution upon him; ablution is required for the one who sleeps lying down, because when a servant sleeps lying down, his joints become loose and relaxed.

It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him and his family) said: Surely, the eye is a strap for the anus, so whoever sleeps should perform ablution.

Sayyiduna Muawiyah bin Abi Sufyan (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: Verily, the eye is a strap for the anus, so when the eyes sleep, the strap is loosened.