Musnad Ahmad 1135:1

Ya'qub narrated to us, my father narrated to us, from Ibn Ishaq, Yazid ibn Abi Habib al-Masri narrated to me, from 'Arak ibn Malik al-Ghifari, [who said]: I heard Nawfal ibn Mu'awiyah al-Dayli—while he was sitting with Ibn 'Umar in the market of Medina—saying: "The prayer that one misses is as if he had been bereaved of his family and his wealth, bereaved of his family and his wealth." He said: Then 'Abdullah—meaning Ibn 'Umar—said: The Messenger of Allah (may Allah bless him and grant him peace) said: "It is the 'Asr [afternoon] prayer."