For the pastoral activity of the Church, the cooperation of a great many people is needed, so that communities as well as individuals may advance to full maturity in faith and continually show forth their faith through the celebration of the liturgy, through study, and through their manner of life. This cooperation is provided by those who devote themselves to catechesis. Enlightened by God's word and the teaching of the Church, catechists impart to others an initiation or a deeper formation in those realities that they themselves have learned as truths to be followed in living and to be celebrated in liturgy.