It is narrated from Sayyiduna Samurah bin Jundub (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever sells goods to two men, the goods belong to the first; and any woman whom two guardians marry off, the marriage by the first is the valid one."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13804