Nicolaus Hunnius on the nature of Faith.
Now if there is any one who hears, understands and believes this [the gospel] to be true, he will receive a firm conviction, that God will have mercy upon him, forgive him his sins, and make him an heir of everlasting life; that Christ the Lord has died for him, and in order to deliver him from his sins, to reconcile him to his heavenly Father and to prepare for him the way unto eternal life, as well as that Christ as suffered, and shed his blood for him, and that he had been delivered for his sins and raised again for his justification.
This faith has its source in the holy scriptures, which induce men to reason thus: It is the will of God that all men should be saved; He loves all men, and is exceedingly anxious that all should be saved and none perish. Christ has been given as a Saviour unto mankind, he has died for all, and reconciled them all unto God. Every one who bears a firm assurance of these facts in his breast, will have no doubts of his having found favour in the sight of God, and forgiveness of sins; as also that he is living in a state of salvation, and that he is to be one day heir of the kingdom of heaven and of everlasting glory. Such firm assurance and such confidence in God constitutes a true faith. By such a faith we are able to appropriate to ourselves the mercies of God and the merits of Christ; and like as God Himself declares that He desires all men to be saved, and that Christ has been given a ransom for many, so in his turn believing man argues again: God desires me to be saved; Christ has become a ransom for me.