Muhammad bin Abd al-Rahman bin Thawban narrated from one of the Companions that when Sayyiduna Ali (may Allah be pleased with him) married Sayyidah Fatimah (may Allah be pleased with her) and intended to consummate the marriage, the Prophet (peace and blessings be upon him) forbade him, saying: "First give Fatimah something." Sayyiduna Ali (may Allah be pleased with him) said: "I have nothing." He (peace and blessings be upon him) said: "Give her your coat of mail." So Sayyiduna Ali (may Allah be pleased with him) gave her the coat of mail and then consummated the marriage.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14462