It is narrated from Sayyiduna Ubadah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "(Exchanging) wheat for barley, two portions for one, hand to hand (is permissible), and it is not proper on credit."
No one narrated this hadith from Qatadah (may Allah have mercy on him) except Sa'id bin Bashir (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الألف / 516
Hadith Takhrij«أخرجه ابن أبي شيبة فى «مصنفه» برقم: 20984»