fear at once yields to assurance

When faith itself is wounded it is as if the soldier's shield were broken at some point from the thrust of the spear, but not in such a manner as to be pierced. For the godly mind will always rise up so as to say with David, "If I walk in the midst of the shadow of death, I shall fear no evils, for thou art with me" [Ps. 22:4, Vg.; 23:4, EV]. Surely it is terrifying to walk in the darkness of death; and believers, whatever their strength may be, cannot but be frightened by it. But since the thought prevails that they have God beside them, caring for their safety, fear at once yields to assurance. However great are the devices, as Augustine says, that the devil throws up against us, while he holds no lodgment in the heart, where faith dwells, he is cast out. Thus, if we may judge from the outcome, believers not only emerge safely from every battle, so that, having received fresh strength, they are shortly after ready to descend again into the arena; but besides, what John says in his canonical letter is also fulfilled: "This is the victory that overcomes the world, your faith" [I John 5:4 p.].

John Calvin, Institutes of the Christian Religion, ed. by John T. McNeill, Book III, Chapter II, Section 21, "The Word of God as the shield of faith," p. 567.