One of the first things Calvin did upon returning to Geneva, Switzerland in 1541 was to provide The Geneva Catechism.
On the importance of catechizing, Calvin said in a letter written Oct 22, 1548,
“The church of God cannot subsist…without catechetical instruction, by which the seed of the future harvest is sown, the people prepared to understand the word preached, and their minds fortified against those who broach novel and strange doctrines.”
Dan Greenfield 