The spiritual climate at the time of Kohlbrugge was greatly influenced by pietism in all of its various forms. I have read several articles and definitions of pietism and found this to be the mindset at the time of Kohlbrugge from “The Rise of Pietism in 17th Century Germany” by Ronald J. Gordan:

“Pietism began to change the emphasis from what Christ has done for us to what Christ does in us. They emphasized holy living rather than the forgiveness of sins. Their theology and practice centered on sanctification (the work of the Holy Ghost in leading us to do good works) rather than justification. Because of this switch in emphasis to sanctification and good works, they fell into legalism and began to confound sanctification and justification, law and gospel. They fell into a subtle form of work-righteousness. As Spener wrote, “As the faith which alone justifies us and makes holy is inseparable from good works, so no one will be justified other than those who are intent upon sanctification." Notice that justification and sanctification are confused. Instead of saying that those who are justified are also sanctified, Spener made justification dependent on one’s desire for sanctification. He inverted the relationship between faith and piety. The just not the sinner is justified in the theology of Pietism.”

Is it any wonder that Kohlbrugge reacted strongly to this form of Pietism and proclaimed loudly the truth of justification alone without works. One of Kohlbrugge’s objections to later Reformed orthodoxy was that it tended to separate sanctification and justification more than the first Reformers, because for them justification was more than just an act. Pieter de Vries writes: “They (the early reformers) stressed that the consolation of justification is received by the believer every time he puts faith in Christ. This emphasis we find also in the writings of Kohlburgge”.

This emphasis, the relation between justification and sanctification, which is found in the writings of Kohlbrugge is also summarized in the Heidelberg catechism question #60:

How art thou righteous before God:

“Only by true faith in Jesus Christ: this is, although my conscience accuses me, that I have grievously sinned against all the commandments of God, and have never kept any of them, and am still prone always to all evil; yet God, without any merit of mine, of mere grace, grants and imputes to me the perfect satisfaction, righteousness and holiness of Christ, as if I had never committed nor had any sins, and had myself accomplished all the obedience with which Christ has fulfilled for me; if only I accept such benefit with a believing heart”.

Because of his strong emphasis on the promises of God, Kohlbrugge has been interpreted in a way that I don't understand, I don't believe how he has been interpreted is truly consistent with his real teaching. It cannot be a wrong emphasis to teach that a Christian always remains a 'poor sinner' trusting in Christ for all of his salvation and a 'debtor to mercy alone.'

On his death bed Kohlbrugge said this:

“My dear children, hold fast to the teaching of the Catechism of Heidelberg. In the first answer of that Catechism it is declared that the only comfort of a Christian is that he belongs to Christ as his complete Saviour. In the second question and answer, it is made clear to us in what way that comfort becomes our personal possession. We have to acknowledge for the first time in our lives and again and again our sin and misery; we have to trust in Christ alone as Saviour, who gives complete deliverance from sin to all his people. Because we are delivered, we have to be filled with gratitude. Gratitude is not a legal activity but a gospel grace. Being saved by grace, it is impossible not to be filled with gratitude and not to regard God as the God of complete salvation. It is the deepest desire of a Christian to glorify God and to enjoy him forever.”

These were the words of the one who was accused of being an antinomian but instead was the ‘Comforter of Mourners’. Those who mourned their sin found great comfort in the teaching of Herman Friedrich Kohlbrugge (1803-1875).