Musnad Ahmad 27:1636

Ishaq ibn Isa narrated to us, Abdullah ibn Zayd narrated to me, my father narrated to me, from Ibn Umar, that he used to dye his garments and apply saffron as a perfume. It was said to him, "Why do you dye this with saffron?" He said, "Because I saw it as the most beloved of dyes to the Messenger of Allah, may Allah bless him and grant him peace; he would apply it as a perfume and dye his garments with it."