Answered by Shaykh Faraz Rabbani
Is it a sin to sleep through prayer unintentionally? Why would this happen?
Answer:
Walaikum assalam,
Outwardly, it is not the sleep that is the sin, because the sleeping person is not morally responsible. Rather, the sin would relate to that which directly led one to miss the prayer, such as sleeping too late, or not taking one’s normally sufficient means to wake up. [As explained by Ibn Abidin in his Radd al-Muhtar]
Inwardly, the scholars say that one rarely misses worship except for sins or wrongs one committed.
And Allah alone gives success.
Wassalam,
Faraz Rabbani.