Sayyiduna Jabir (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever gives as dower his two palms full of wheat, or dates, or sawiq (barley meal), or flour, has made (her) lawful (for himself)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14371