Ibn Abi Mulaykah (may Allah have mercy on him) said: A woman was brought to me claiming that her companion had stabbed her with an awl until it came out through her palm. So I asked Ibn Abbas (may Allah be pleased with them both), and he said that the Messenger of Allah (peace and blessings be upon him) said: "If people were given on the basis of their claims, men would claim the wealth and blood of other men; but the proof is upon the one who makes the demand, and the oath is upon the one from whom it is demanded."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 21200