A catechism ( /ˈkætəkɪzəm/; Ancient Greek: κατηχισμός from kata = "down" + echein = "to sound", literally "to sound down" (into the ears), i.e. to indoctrinate) is a summary or exposition of doctrine, traditionally used in Christian religious teaching from New Testament times to the present. Catechisms are doctrinal manuals often in the form of questions followed by answers to be memorized, a format that has been used in non-religious or secular contexts as well.

Development and usage of systematic catechisms is unique to Western Christianity. Besides some exception, training catechumens in Eastern Christianity is carried out in case by case. As defined in the Catechism of the Catholic Church, paragraph 5 (quoting John Paul II, Apostolic Exhortation Catechesi tradendae 18):

Catechesis [/ˌkætəˈkiːsɪs/ —WP] is an education in the faith of children, young people and adults which includes especially the teaching of Christian doctrine imparted, generally speaking, in an organic and systematic way, with a view to initiating the hearers into the fullness of Christian life.

Paul David Washer (born 1961) is the Founder/Director & Missions Coordinator of HeartCry Missionary Society which supports indigenous missionary work. He is also a Southern Baptist itinerant preacher. Washer's sermons tend to have an evangelistic focus on the gospel and the doctrine of the assurance of salvation, and he frequently speaks against practices such as the sinner's prayer, and a focus on numerical church growth.

Washer had a born again experience while studying to become an oil and gas lawyer at the University of Texas. Upon graduation, he attended Southwestern Baptist Theological Seminary and achieved a Master of Divinity degree. He then moved to Peru to become a missionary for 10 years, after which he returned to the United States. Washer resides in Radford, Virginia, where he lives with his wife and three children.

Washer's sermons often focus on the character of Christ and how a person is saved from hell. According to Washer, a person is saved through faith alone, but the evidence of a person's repentance is by walking with Jesus. Washer claims that most people who profess a belief in Christianity aren't truly saved. Washer blames preachers, as he claims many preachers often say a person is saved without looking for evidence of repentance in that person's life.

Scott Hahn (born October 28, 1957) is a contemporary author, theologian, and Catholic apologist. His works include Rome Sweet Home and The Lamb's Supper: The Mass as Heaven on Earth. His lectures have been featured in multiple audio distributions through Lighthouse Catholic Media. He currently teaches at the Franciscan University of Steubenville, a Catholic university in the United States.

Hahn received his B.A. in 1979 from Grove City College in Pennsylvania with a triple major of theology, philosophy, and economics (magna cum laude). He obtained his M.Div. (summa cum laude) from Gordon-Conwell Theological Seminary in 1982. In May 1995, he was awarded a Ph.D. in systematic theology from Marquette University (Phi Beta Kappa). His dissertation, entitled Kinship by Covenant: A Biblical Theological Analysis of Covenant Types and Texts in the Old and New Testaments, is an example of contemporary covenantal theology^{[citation needed]}.

Hahn started out as a Presbyterian minister and theologian with years of ministry experience in congregations of the Presbyterian Church in the United States of America or PC(USA), and Professor of Theology at Chesapeake Theological Seminary.