Musannaf Ibn Abi Shayba 33:1325

Sa'id ibn 'Abd Allah ibn al-Rabi' ibn Khuthaym narrated to us, from Nusayr ibn Dhu'luq, from Bakr ibn Ma'iz, who said: When 'Abd Allah ibn Mas'ud would see al-Rabi' ibn Khuthaym approaching, he would say: "And give good tidings to the humble [al-mukhbitin]." By Allah, if the Messenger of Allah, may Allah bless him and grant him peace, had seen you, he would have loved you.