that a freed a slave girl of his came to him, and said: "Times have become hard on me and I want to go to Al-'Iraq." He said: "Why not to Ash-Sham the land of the resurrection? Have patience you foolish lady; I heard the Messenger of Allah (ﷺ) say: 'Whoever endures its hardships and difficulties (Al-Madinah) then I will be a witness, or an intercessor for him on the Day of Judgement." There are narrations on this topic from Abu Sa'eed, Sufyan bin Abi Zuhair, and Subai'ah Al-Aslamiyyah.
Jami` at-Tirmidhi Book 49, Hadith 318