The Prophet ﷺ said, "Most of the punishment of the grave is due to urine."
حدثنا عفان حدثنا أبو عوانة عن سليمان الأعمش عن أبي صالح
عن النبي ﷺ قال إن أكثر عذاب القبر من البول
Its isnad is sahih. It occurred previously at 8313. Ibn Majah narrated it, 1/125, no. 348, in the Book of Purification, the chapter on strictness regarding urine. Daraqutni also narrated it, 1/128, as did Hakim, 1/183, who graded it sahih, and Dhahabi agreed with him.