Musnad Ahmad 855:8

Hashim narrated to us, Abd al-Samad ibn Habib ibn Abdullah al-Azdi narrated to us, he said: My father narrated to me, from al-Hakam ibn Amr al-Ghifari, he said: I and my brother, Rafi ibn Amr, entered upon the Commander of the Faithful, Umar ibn al-Khattab. I was dyed with henna, and my brother was dyed with saffron. Umar ibn al-Khattab said to me: "This is the dye of Islam." And he said to my brother, Rafi: "This is the dye of faith."