Chapter 18.4, part two

iv. True believers may have the assurance of their salvation divers ways shaken, diminished, and intermitted; as, by negligence in preserving of it; by falling into some special sin, which woundeth the conscience, and grieveth the Spirit; by some sudden or vehement temptation; by God's withdrawing the light of his countenance and suffering even such as fear him to walk in darkness and to have no light: yet are they never utterly destitute of that seed of God, and life of faith, that love of Christ and the brethren, that sincerity of heart and conscience of duty, out of which, by the operation of the Spirit, this assurance may in due time be revived, and by the which, in the meantime, they are supported from utter despair. 
Most (or maybe all) Christians have their doubts. Suddenly the message of the gospel seems quite implausible. Or painful suffering causes us to question the goodness of God. Or an awareness of our sin leads us to doubt whether God could ever love someone like us. Our faith is shaken--or, more accurately, the assurance of our faith is shaken, at least for a season.

The Westminster Confession is honest enough about the difficulties of life to admit that doubt can play a large role in Christian experience. True believers sometimes walk in such great darkness that they cannot see the light.

Yet our faith will prevail. God has put his seed within us--the seed of faith. Thus, even in our doubts we still have at least some small measure of faith in the gospel, some trust in Christ, some love for the church, and some sense of our duty. In time, this seed will sprout again, and grow, so that our lives may flower with the fruit of the assurance of faith.

Ultimately, what renews our assurance is the Holy Spirit, who is always working within us to call us to Christ. Once again, the Confession showcases the Third Person of the Trinity--this time by showing us the work of God the Holy Spirit in reviving the assurance of our faith. 

Knowing the power of God's Spirit to grant assurance to our faith guards our hearts against absolute despair. When our faith starts to feel shaky, we should not give in to our doubts and fears, but believe that the Holy Spirit has the power to restore the full assurance of our faith. 

Dr. Philip Ryken is the president of Wheaton College and the author of numerous books, the most recent of which is Loving the Way Jesus Loves (Crossway, 2012).