Allah's Apostle said, "May Allah's mercy be on him who is lenient in his buying, selling, and in demanding back his money."
Sahih Bukhari: Volume 3, Book 34, Number 290
Allah's Apostle said, "If I had not found it hard for my followers or the people, I would have ordered them to clean their teeth with Siwak for every prayer."
Sahih Bukhari: Volume 2, Book 13, Number 12