"Third, we are here to mark and to remember with care the foundation of infallible certainty of man's salvation. For if man is bound in conscience first, to give assent to the gospel and, second to apply it to himself by true faith, then without doubt a man by faith may be certainly persuaded of his own election and salvation in this life without any extraordinary revelation, God's commandments being in this and the like cases possible. For commandments are either legal or evangelical. Legal [commandments] show us our disease, but give us no remedy. And the perfect doing of them, according to the intent of the Law-giver, by reason of man's weakness and through man's default, is impossible in this world. As for evangelical commandments, they have this privilege, that they may (and can) be performed according to the intention of the Law-giver in this life, because with the commandments is joined the inward operation of the Spirit to enable us to effect the duty commanded. And the will of God is not to require absolute perfection at our hands in the gospel as in the law, but rather to qualify the rigor of the law by the satisfaction of a Mediator in our stead, and of us (being in Christ) to accept the upright will and endeavor for the deed, as the will to repent and the will to believe for repentance and true faith indeed. Now then, if things required in the gospel are both ordinary and possible, then for a man to have an infallible certainty of his own salvation is both ordinary and possible." William Perkins pg. 25 'The Works of William Perkins' Volume 8 'A Discourse of Conscience'