Why is the Holy Spirit telling me to say things even if others hate me for it?

If the world hates you it hated Me before it hated you.  This was Jesus speaking and they hated Him without a cause - so if you are of Christ, they will hate you also (John 15:18 on to verse 25)

“If the world hates you, you know that it has hated Me before it hated you.

“If you were of the world, the world would love its own; but because you are not of the world, but I chose you out of the world, because of this the world hates you." (John 15:18-19).