What is the ruling on sleeping before the prayer time without taking measures to wake up, and what are the views of the four schools of thought, Ibn Taymiyyah, and others on this? Does the ruling differ between someone who does this rarely and someone who does it regularly?

Scholars have differed on the ruling of sleeping before the time of prayer if it is highly probable that one will miss the prayer. Some have forbidden it, while others have permitted it.

It is worth mentioning that some scholars have obligated taking measures to aid in waking up for prayer.

As for the Hadith: "As for the one whose head is crushed with a rock, he is one who takes the Qur'an and rejects it, and sleeps through the obligatory prayer," this applies to someone who sleeps and does not care about prayer, unlike someone who is overcome by sleep despite their eagerness to perform it. In such a case, "there is no negligence in sleep."