Heidelberg Catechism, Lord's Day 34
Lord's Day 34 of the Heidelberg Catechism addresses the believer's assurance of salvation and the work of the Holy Spirit in sanctification. This catechetical instruction serves as a foundational Reformed confession suitable for Christian education and pastoral instruction on the doctrines of justification and progressive holiness.
[Lord's Day 34 text - parse manually from https://www.crcna.org/welcome/beliefs/confessions/heidelberg-catechism]