The story of AIi bin Ma'bad: (Rahmatullah alaih)

Ali bin Ma'bad (Rahmatullah alaih) is a Mohaddith. He says:

"I was living in a rented house. Once I wrote something which I wanted to dry up quickly. The house walls were of mud and I intended to scrape a little mud from there to dry up the ink. But I thought: 'This house is not mine, and I cannot scrape the walls with-out the owner's permission.
After a moment I reflected: 'After all what difference does it make? It is only a very little mud that I am using.' So, I scraped a little mud from a wall and used it. That night, while asleep, I saw a person in my dream, admonishing me: 'Perchance tomorrow, on the Day of Judgement, you may rue that saying of yours:

(It is, only a very little mud that I am using)
The dictates of piety are different with different persons. The high rank of the Mohaddith demanded that he should have been scrupulous even about a small quantity of mud, though for a common man it was insignificant and therefore within permissible limits.