Abdullah bin Hudhaym (may Allah have mercy on him) narrates from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), that he (peace and blessings be upon him) was very careful to keep himself clean of urine (splashes), and he ordered his Companions to do the same. Mu'adh (may Allah be pleased with him) said: "Most of the punishment of the grave is because of urine." Ibn Abi Maryam narrated it as the hadith of Abdullah bin Hurayth.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17384