Justification, Sanctification and Perseverance - By Grace through Faith

Berkouwer's work on Faith and Justification is undergirded by this foundation - principle:
"The character of faith resolves all tensions between objectivity and subjectivity, For faith has significance only in its orientation to its object - the grace of God" (p. 29).
His work on Faith and Sanctification is undergirded by the same principle:
"The sanctification ... demanded is always an implicate of the sanctification that originates in God's mercy. Hence the sanctification of believers is never an independent area of human activity ... we can speak truly of sanctification only when we have understood the exceptionally great significance of the bond between Sola-fide and sanctification ... the Sola-fide ... a confession of 'By grace alone we are saved' ... is the only sound foundation for sanctification" (pp. 26, 42-43).
His work on Faith and Perseverance is built on this same foundation:
"The perseverance of the saints is not primarily a theoretical problem but a confession of faith ... a song of praise to God's faithfulness and grace" (p. 14).
Berkouwer's principle for understanding justification, sanctification and perseverance may be summed up thus:
"Sola fide (faith alone) and sola gratia (grace alone) ... mean the same thing" (Faith and Justification, p. 44).