Musnad Ahmad 27:1368

Affan narrated to us, al-Hasan ibn Abi Ja'far narrated to us, from Ayyub, from Nafi', from Ibn Umar, from the Prophet (peace and blessings of Allah be upon him), who said: "Whoever is able to die in Medina, let him die there, for I will intercede for whoever dies in it."