Edwards on how God does not give assurance:
God’s manner is not to bring comfortable texts of Scripture to give men assurance of his love and of future happiness, before they have had a faith of dependence. And if the Scripture which comes to a person’s mind be not so properly a promise as an invitation; yet if he makes the sudden or unusual manner of the invitation’s coming to his mind the ground on which he believers that he is invited, it is not true faith; because it is built on that which is not the true ground of faith (emphasis added).
This means that some people feel assured of God’s saving love for them before they have faith and thereby think that God is securing salvation for them. This is impossible, because if someone does not have faith in God, they cannot please him (Heb. 11:6) and therefore cannot be justified before him (Rom. 3:28; 5:1).
It is not enough to know facts about God. The Bible is not about information; it is about transformation. If the words of God do not, by his miraculous grace, transform someone from death to life and move them past knowing facts to true, believing faith, there will be no salvation. Edwards puts it this way: “The external idea a man has now of Christ hanging on the cross, and shedding his blood, is no better in itself than the external idea that the Jews His enemies had, who stood round His cross, and saw this with their bodily eyes.”
What we need is a new set of spiritual eyes. The eyes we are born with are blinded. Only God can give these new eyes. And when these new eyes are received, full assurance of love and future happiness will most certainly come.