The inclusion of “ready” amounts to a confession that Jesus is already seated on his judgment seat. The reference is to his ascension and exaltation so that, as Jesus had told his disciples, “all authority in heaven and on earth is given to me” (Matthew 28:19). It is not so that Christ needs yet to earn and/or acquire the throne (and hence the licence to judge); rather, this authority has already been committed to Jesus. So the coming judgment is certain, a reality that gives confidence to those suffering abuse for their faith in this life.
5 but they will give account to him who is ready to judge the living and the dead.