If you call the persecutors of the prophets your fathers, stop trying to pretend you are different from them. Be what you really are and let sham and hypocrisy be set aside.
It is a fearful thing to harden the heart against God, for there is a limit to his patience towards the rebellious. If I harden my heart today, how do I know that all further gracious influences of the Spirit will not be withdrawn from me by tomorrow? Do I imagine I can come to Christ any day I choose? Do I not understand that I am dependant on him to overcome the resistance of my heart? Therefore I ought to cooperate with every sweet inclination that God works within me. Once a person is hardened, they will never again have any genuine desires to find the Lord.