Muhammad narrates from Sayyiduna Abu Hurayrah (may Allah be pleased with him): "Ibrahim (peace be upon him) told only three lies." He mentioned the hadith as mawquf, (and said) that while he was in the land of one of the tyrants and Sarah (may Allah be pleased with her) was with him, that king was told: 'Here is a man who has with him a woman more beautiful than all people.' So he summoned Ibrahim (peace be upon him) and asked: "Who is this woman?" He said: "She is my sister." He said: "Go and send her to me." (Ibrahim) came to Sarah (may Allah be pleased with her). Ibrahim (peace be upon him) said: "If he asks you, tell him that you are my sister; do not contradict me before him, for there is no Muslim on the face of the earth besides me and you; you are my sister in Islam." The narrator says: She went, and he mentioned the rest of the hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 15145