Musannaf Ibn Abi Shayba 13:2812

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Shu’bah, he said: I asked al-Hakam and Hammad about a man who lends a man dirhams, and he gives back better than them. They both said: There is no harm in it, as long as his intention was not [based] upon that.