The footnote on the title of this section tells us it was derived from 1971’s General Catechetical Directory, number 71. We’ll also get a more in-depth look later in the GDC in Part V, Chapters 1 and 2 (sections 230 through 250). Today we get a first, quick summary. And though this is a short section, it contains the very basic requirements or considerations for a parish catechist. If I were a faith formation director, I would make sure these qualities were the measuring stick for discerning good people in this ministry.
156. No methodology, no matter how well tested, can dispense with the person of the catechist in every phase of the catechetical process. The charism given to (her or) him by the Spirit, a solid spirituality and transparent witness of life, constitutes the soul of every method. Only (her or) his own human and Christian qualities guarantee a good use of texts and other work instruments.
Three primary points: a charism to teach, personal spirituality, and life’s witness in the faith.
The catechist is essentially a mediator. He (or she) facilitates communication between the people and the mystery of God, between subjects amongst themselves, as well as with the community. For this reason, his (or her) cultural vision, social condition and lifestyle must not be obstacles to the journey of faith. Rather, these help to create the most advantageous conditions for seeking out, welcoming and deepening the Christian message. He (or she) does not forget that belief is a fruit of grace and liberty. Thus, he (or she) ensures that his (or her) activities always draw support from faith in the Holy Spirit and from prayer. Finally, the personal relationship of the catechist with the subject is of crucial importance.
I like the first sentence. I train liturgical ministers with the same grounding. Catechists are essentially porters. They invite the relationship between the believer and God. They cannot command it, but human sin can certainly block it.
This paragraph also gives an important checklist for discernment, either for a prospective catechist or one renewing a commitment.
- Willing and able to facilitate relationships amongst students and with the community?
- No personal obstacles for others?
- Acknowledgement of God’s grace in one’s service?
- A ministry grounded in prayer and the spiritual life?
- A personal relationship with those served?
Catholic Sensibility 
This is very encouraging to all catechists,how can one get hard copies?
A new edition is out: https://www.vaticannews.va/en/vatican-city/news/2020-06/vatican-publishes-new-directory-for-catechesis.html#:~:text=%20New%20Directory%20for%20Catechesis%20released%20%201,highlights%20the%20importance%20of%20%E2%80%9Cwelcoming%20and…%20More%20