"I am riding to the Jews tomorrow. Do not initiate the greeting with them, and if they greet you, then say: Wa 'alaikum (and also upon you)". (Using translation from Ibn Mājah 3699)  

لَنَا رَسُولُ اللهِ ﷺ إِنِّي رَاكِبٌ غَدًا إِلَى يَهُودَ فَلَا تَبْدَءُوهُمْ بِالسَّلَامِ وَإِذَا سَلَّمُوا عَلَيْكُمْ فَقُولُوا وَعَلَيْكُمْ