You need net be surprised if the world hate you. "The world," κόσμος (five times used in strongly emphatic manner), is humanity apart from grace. This world will despise and hate your mutual love, will scorn your love to itself for my sake; will detest the higher and unworldly standard which you will set up.
But here is some consolation. Know ( γινώσκετε imperative, as μνημονεύετε in John 15:20) that it has hated me before (it hated) you. "Me first, me most" (Lange). "The superlative contains the comparative" (Tholuck).
"This hatred is a community of destiny with me" (Meyer). You know how it has hated me, and hunted me from Bethlehem to Egypt, from Nazareth to Capernaum, from Gergesa to Jerusalem. Be not surprised if it hate you.