{6} If the world hate you, ye know that it hated me before it hated you.

(6) When the faithful ministers of Christ are hated by the world as their master was, it should not cause them to fear, but rather strengthen and encourage them.

People's New Testament

15:18 If the world hate you. The world is the unregenerate portion of mankind. It hated and slew the Lord. It has never loved his disciples. Satan is its prince.

Scofield Reference Notes

Margin world

kosmos = world-system. Jn 16:11,33 7:7. See Scofield Note: "Rev 13:8".

Matthew Henry's Concise Commentary

15:18-25 How little do many persons think, that in opposing the doctrine of Christ as our Prophet, Priest, and King, they prove themselves ignorant of the one living and true God, whom they profess to worship! The name into which Christ's disciples were baptized, is that which they will live and die by. It is a comfort to the greatest sufferers, if they suffer for Christ's name's sake. The world's ignorance is the true cause of its hatred to the disciples of Jesus. The clearer and fuller the discoveries of the grace and truth of Christ, the greater is our sin if we do not love him and believe in him.