Sunan Abi Dawud Book 2, Hadith 68
I asked Ibn 'Umar about the gravel spread pin the mosque. He replied: One night the rain fell and the earth was moistened. A man was bringing the gravel (broken stones) in his cloth and spreading it beneath him. When the Messenger of Allah (ﷺ) finished his prayer, he said: How fine it is !
I said: Messenger of Allah, tell us the legal injunction about (visiting) Bayt al-Muqaddas (the dome of the Rock at Jerusalem). The Messenger of Allah (ﷺ) said: go and pray there. All the cities at that time were effected by war. If you cannot visit it and pray there, then send some oil to be used in the lamps.
It was said that when a man removed gravels from the mosque, they adjured him.