Musannaf Ibn Abi Shayba 13:1189

Abu Bakr narrated to us, he said: Kathir bin Hisham narrated to us, from Ja'far bin Burqan, he said: 'Abd al-Malik bin Abi al-Qasim narrated to us, he said: I asked Nafi' and Rabi'ah, and I said: "We buy cloth, then we add to its price, then we mark it upon it, then we sell it as *murabahah* (cost-plus profit) without disclosing the increase." They said: "No, this is *al-mukhalabah* (deception) and *al-mukadhabah* (lying)."