Abd al-Rahman bin Qays bin Muhammad bin al-Ash'ath bin Qays narrates from his father, and he from his grandfather, that al-Ash'ath (may Allah be pleased with him) bought some slaves from the slaves of the khums from Abdullah (may Allah be pleased with him) for twenty thousand, and Abdullah (may Allah be pleased with him) sent someone to him to collect their price. Al-Ash'ath (may Allah be pleased with him) said: I took them for ten thousand. Abdullah (may Allah be pleased with him) said: Choose a man to judge between me and you. Al-Ash'ath (may Allah be pleased with him) said: You are (the judge) between me and yourself. Abdullah (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "When the two parties to a sale disagree and there is no proof between them, the word of the owner of the goods is accepted, or else they both abandon (the sale)."
This is a hasan (good), connected chain, and it has also been narrated through several ways with mursal chains which, when combined, make the hadith strong.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10804
Hadith Gradingمحدثین:حسن لغيره
Hadith Takhrij«حسن لغيره۔ اخرجه ابوداود 3511۔ الحاكم 2/ 52»