Musannaf Ibn Abi Shayba 13:2076

Abu Bakr narrated to us, he said: Abd al-A’la narrated to us, from Ma’mar, from al-Zuhri, from Sa’id ibn al-Musayyib, from Abu Hurayrah, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Do not practice najash (bidding up the price of an item without the intention of buying it)."