Is delaying prayer past its prescribed time without performing it considered an act of disbelief (kufr), necessitating the utterance of the Two Testimonies (Shahadatayn), performing ghusl, and repeating the prayer, or is it merely a sin? What is the view of the four schools of thought on this, and which one is the most correct?

Intentionally missing a single prayer until its time has expired, without a valid Sharia-compliant excuse, is a grave major sin. Delaying a prayer beyond its time intentionally is also among the major sins. Whoever intentionally misses a single prayer has committed a grave major sin, and merely making up the prayer (qada') does not remove the sin of what he has done, by the consensus of Muslims. The one who misses a single prayer out of laziness is not considered to have committed an act of disbelief that expels him from the fold of Islam, and this is the view of the majority of scholars. However, he is obligated to make it up. The majority of scholars hold that he should be executed for abandoning it if he lets its time expire.