Ubaydullah bin 'Abdullah bin 'Utba عبيد الله بن عبد الله بن عتبة بن مسعود · The Book of Purification

"A Bedouin stood up and urinated in the Masjid, ans the people started shouting. The Messenger of Allah (ﷺ) said to them: 'Leave him alone, and spill a bucket of water over his urine. For you have been sent to make things easy for people, you have not been sent to make things difficult.'"

It contains greasiness.

"A small boy was brought to the Messenger of Allah (ﷺ) and he urinated on him, so he called for water and poured it on the place where the urine was."

"We did Tayammum with the Messenger of Allah (ﷺ) using dust, and we wiped our faces and our arms up to the shoulders."

"We were with 'Umar when a man came to him and said: 'O Commander of the Believers! sometimes we stay for a month or two without finding any water. Umar said: As if I did not find water, I would not pray until I found water.' 'Ammar bin Yasir said: 'Do you remember, O Commander of the Believer, when you were in such and such a place and we were rearing the camels, and you know that we became Junub?'…