Ata' bin Ya'qub narrates: Ibn Umar (may Allah be pleased with them both) borrowed one thousand dirhams from me as a loan, then repaid me with dirhams better than them. I said to him: Your dirhams are better than my dirhams. He said: "Whatever excellence was in them has reached you from me (as a gift, not as part of the loan)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13015