The Messenger of Allah ﷺ said to them one day, "I am riding out to the Jews. Whoever wishes to come along with me, if they greet you with salaam, say, 'And upon you.'"So we set out, and when we came to them, they greeted us, and we replied, "And upon you."
قال رسول الله ﷺ لهم يوما إني راكب إلى يهود فمن انطلق معي فإن سلموا عليكم فقولوا: وعليكم فانطلقنا فلما جئناهم سلموا علينا فقلنا وعليكم.
Ahmad (27235) narrated it, and this is his wording, as did Nasai in Kubra (10148) in abbreviated form, through various routes from Abdul-Hameed bin Jafar, who said, Yazid bin Abu Habib told me, from Marthad bin Abdullah, from Abu Basra Ghifari, who related it. Its chain of transmission is hasan because of Abdul-Hameed bin Jafar, for he is truthful.Ahmad (27226) also narrated it through the route of Ibn Lahia, who said, Yazid bin Abu Habib told us, from Abu Khayr (that is, Marthad bin Abdullah), who said, I heard Abu Basra relate something similar in abbreviated form, with an addition, "So do not greet them first with the salam." Ibn Lahia has known issues regarding his reliability.