Musnad Ahmad 27:1476

Ishaq narrated to us, Malik narrated to me, from Qatan ibn Wahb or Wahb ibn Qatan al-Laythi—Ishaq was uncertain—from Yuhannis, the freed slave of al-Zubayr, who said: I was with Ibn Umar when a freed slave woman of his came to him and mentioned the severity of the situation, and that she wanted to leave Medina. He said to her: "Sit, for I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'No one among you will endure its hardship and its severity except that I will be an intercessor for him—or a witness—on the Day of Resurrection.'"