Confessing Christ with one’s mouth is not something that a person does to be justified; it is something a justified person does.  Those who are justified are ashamed of their sin and proud of their Savior!   Just as it is natural for a newborn baby to open its mouth and cry, so it is only natural for a sinner saved by grace to open his mouth and give full credit to Christ.  “Let the redeemed of the Lord say so!” (Psalm 107:2).  “Saying so” is not something that a person does to be redeemed; it is something a redeemed person does!”