The Heidelberg Catechism is a teaching guide about the Christian faith, written in 1563 in Germany. It was created to help bring unity among Christians and to explain the beliefs of the Reformed (or Calvinist) churches in a clear and personal way.
The catechism is written in a question-and-answer format and focuses on three main parts:
(1) Q1 to Q11 – Human sin and misery
(2) Q12 to Q85 – How God saves us through Jesus
(3) Q86 to Q129 – How we should thank God by living a good life
Even today, many churches still use it to teach people about the Bible and Christian faith, because it speaks to both the mind and the heart.