Musnad Ahmad 658:52

Ibrahim ibn Mahdi narrated to us, he said: Salih ibn Umar narrated to us, from Yazid ibn Abi Ziyad, from Abd al-Rahman ibn Abi Layla, from al-Bara’, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever calls Medina 'Yathrib', let him seek the forgiveness of Allah, the Almighty and Majestic. It is Taba, it is Taba."