What is the ruling on one who prays without Wudu'?

Whoever intentionally prays without ablution (wudu), while water is available and they are able to use it, has committed a major sin. Some scholars, like the Hanafis, have gone so far as to consider the perpetrator an apostate for mocking the Sharia (definition), while others believe that one does not become an apostate unless they deem it permissible, even if they deserve blame and punishment. A severe warning has been reported for those who do this; it has been mentioned that a servant was beaten in his grave for praying without purification. As for one who cannot find water or is unable to use it, they should perform tayammum (definition) instead.