With the coming of the Reformers the idea of Assurance began to develop theologically. Martin Luther based his doctrine of assurance almost entirely upon the complete and sole trust in Christ and His atoning work. In other words, saving faith and assurance go hand in hand . Huldrych Zwingli took Luther’s view further. He agreed that assuring faith was a complete surrender of ones self to God. However, Zwingli based his assurance upon election. Election is a work of God and assuring faith is a result of God’s work. Hence a believer, through assuring faith, can see his election and calling. It is a certain sign. Assuring faith was not passive. Therefore good works, although holding no influence in terms of one’s salvation, are; (i) necessary for faith, (ii) an assuring sign of faith (iii) a valuable support for assurance. Zwingli underscores all this by insisting that all evidences are ultimately the work of the Holy Spirit. However, it is the reformer john Calvin who really developed a detailed understanding of the doctrine of assurance.
Calvin believed that faith was founded upon knowledge. This knowledge was the gospel of Jesus Christ as found in the word of God. Faith based on anything else would “lead miserable souls astray rather than direct them to a definite goal” .
However, Calvin goes on to define further both faith and knowledge. To merely know something of God’s will is not be accounted faith:
“We hold faith to be knowledge of God’s will towards us, perceived from his word. But the foundation of this is a preconceived conviction of God’s truth. As for certainty, so long as your mind is at war with itself, the word will be of doubtful and weak authority, or rather of none. And it is not even enough to believe that God is trustworthy, who can neither deceive nor lie unless you hold to be beyond doubt that whatever proceeds from him is sacred and inviolable truth” .
In other words one can have knowledge of God’s word, but not believe it to be absolute truth. This renders the knowledge doubtful and weak. This raises the question of the place of such people.