Imam al-Shafi'i (may Allah have mercy on him) said: "It will be said (to him): 'You are both equal in the claim and in the proof (testimony), and the one in whose possession it (the item) is has, by virtue of its being in his possession, a ground that is stronger than your ground; so it will be his on account of the greater strength of his ground. And there is (also) a Sunnah on this matter in line with what we have said.'"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / Q21223
Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) said that two people made a claim over an animal, and both had witnesses that it was his mount; so the Messenger of Allah (peace and blessings be upon him) gave judgement in favour of the one in whose possession it was.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / 21223
Sayyiduna Jabir (may Allah be pleased with him) said that two men came to the Messenger of Allah (peace and blessings be upon him) with a dispute over a she-camel, (each claiming) that it had been born in his care, and they presented testimony; so he (peace and blessings be upon him) "gave judgement in favour of the one in whose possession it was."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / 21224
Ayyub narrates from Muhammad that two men came to Qadi Shurayh (may Allah have mercy on him) with a dispute over an animal, and each also had testimony that it had been born in his care; so Qadi Shurayh (may Allah have mercy on him) also gave judgement in favour of the one in whose possession (it) was, (and said): The one in whose care it was born has more right than the one who (merely) recognises it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / 21225
Ibn Sirin (may Allah have mercy on him) narrates from Qadi Shurayh (may Allah have mercy on him) that two men came to him with a dispute over a riding animal. One of them, in whose possession it was, presented witnesses that the animal had been born in his care, and the other presented witnesses that it was his animal which he recognised. So Qadi Shurayh (may Allah have mercy on him) said: The one in whose care the animal was born has more right than the one who (merely) recognises it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / 21226