“The benefit of justification through faith alone has in it a rich comfort for the Christian.
The forgiveness of his sins, the hope for the future, the certainty concerning eternal salvation, do not depend upon the degree of holiness which he has achieved in life, but are firmly rooted in the grace of God and in the redemption which is in Christ Jesus.
If these benefits had to derive their certainty from the good works of the Christian they would always, even unto death, remain unsure, for even the holiest of men have only a small beginning of perfect obedience.
Accordingly, the believers would be constantly torn between fear and anxiety, they could never stand in the freedom with which Christ has set them free, and, nevertheless being unable to live without certainty, they would have to take recourse to church and priest, to altar and sacrament, to religious rites and practices.
Such is indeed the condition of thousands of Christians both inside and outside of the Roman church. They do not understand the glory and the comfort of free justification.
But the believer whose eye has been opened to the riches of this benefit, sees the matter differently. He has come to the humble acknowledgement that good works, whether these consist of emotional excitements, of soul experiences, or of external deeds, can never be the foundation but only the fruit of faith.
His salvation is fixed outside of himself in Christ Jesus and His righteousness, and therefore can never again waver. His house is built upon the rock, and therefore it can stand the vehemence of the rain, the floods, and the winds.”
–Herman Bavinck, The Wonderful Works of God (trans. Henry Zylstra; Glenside, PA: Westminster Seminary Press, 1909/2019), 447.