Musannaf Ibn Abi Shayba 16:305

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Sufyan, from Abd al-Rahman ibn al-Qasim, from his father, he said: A delegation from Thaqif came to Abu Bakr. Food was brought, and the people drew near, but a man who had this disease—meaning leprosy—kept to the side. Abu Bakr said to him, "Draw near." So he drew near. He said, "Eat." So he ate, and Abu Bakr began to place his hand where the man’s hand was.