How can we follow Christ even at a distance while fighting and killing? Calvin gives us an indication by pointing out that Christ's pacific nature (his willingness to suffer violence at the hands of Jewish and Roman authorities) is grounded in the priestly office of reconciliation and intercession that is reserved for him alone. Christ's pacific nature is thus inextricably tied to his role as redeemer and cannot be intended as a model for Christian behavior. No Christian can or should try to act as a redeemer, but all can and should follow Christ in obeying the commands of the Father. And the Father commands the just use of force.

What did he mean then by all that "follow me" business?

There is really good bunch of articles at faithmaps that explore both sides of this ugly mess...