The Prophet ﷺ said, "Most of the punishment of the grave is due to urine."
حدثنا يحيى بن حماد حدثنا أبو عوانة عن الأعمش عن أبي صالح
عن النبي ﷺ قال أكثر عذاب القبر في البول
Its chain of transmission is sahih. Ibn Majah related it in the chapter on purification, from Abu Bakr bin Abu Shayba. Many hadiths have been narrated warning against getting any urine on oneself, because of what this entails regarding the invalidity of prayer. Bazzar and Tabarani in Al-Kabir, along with Hakim and Daraqutni, all related through Abu Yahya Qattat, from Mujahid, from Ibn Abbas, may Allah be pleased with him, who said, the Messenger of Allah ﷺ said, "Most of the punishment of the grave is due to urine, so guard yourselves carefully against urine." Among these narrations is also what was related from Anas, may Allah be pleased with him, who said, the Messenger of Allah ﷺ said, "Guard yourselves carefully against urine, for most of the punishment of the grave comes from urine." Daraqutni related it.