Irenaeus made a significant contribution to epistemology, psychology, and asceticism in late antiquity by establishing the first fully developed Christian framework for ascetic training that has come down to us. Irenaeus innovated in epistemology and psychology to direct the daily, embodied ascetic practices that enabled human beings to make progress towards union with God. Irenaeus developed an empirical epistemology from his physics of creation ex nihilo that focused ascetic training on structuring embodied perceptions in order to develop the ability to accurately discern the truth and to reliably choose the good. He produced a holistic psychology from his physics of embodiment that focused on training the soul to grasp the truth, have virtuous emotions, choose righteous actions, and follow the desires of the Spirit. Irenaeus taught that practising the ascetic disciplines of vigilant attention, meletē, and egkrateia every day was essential for structuring perception to grasp the essence of phenomena ‘as they are’, unveiling the true value of faith, righteousness, and union with God as the highest human good, and living an embodied life capable of enjoying the good without end.

The catechumenate emerged in the late second century during the period when Christianity was transitioning from a loose collection of school churches to a more unified monepiscopate. Irenaeus’s writings bear witness to the aesthetic character of knowledge in early Christian catechetical teaching during this time. For Irenaeus, the rule of truth serves as a pedagogical tool enabling new Christians to perceive the unity of creation and Scripture. This chapter looks at catechetical terminology and appeals to the Rule of Truth in Aduersus haereses and the Demonstratio.

Irenaeus’ view is condensed in the collection that he brought together, combining the Book of Acts with the so-called Catholic Letters (= the Praxapostolos). Placed after the four Gospels, it endorses a neatless development from Jesus and his early followers through the early days of growth of the church in its emancipation from its Jewish beginnings. With Paul’s letters in a revised version that was made to fit the Gospels and the Praxapostolos this fiction of a continuous, rapid and Spirit-guided growth was linked to the success-story of the Church in contra-distinction to the miseries and decline of the Jewish community and the vain attempts at undermining the Church by the develish heretics.

The first principles behind the developmental idea are linear time, interiority and staged structure. ‘Development’ is one particular historical way of conceptualizing the primary principle of change; in it, human time is an attempt at successful ‘recapitulation’ (a term that would reappear with modern developmental psychology’s founder, G. Stanley Hall) of Adam’s initial failure. In monotheism, time constructs interiority as permanence, ‘the mind’, in contrast with the temporary visitations of pagan or shamanic religion. Medieval psychology saw a proliferation of its ‘faculties’ (memory, imagination, judgement) and ‘operations’ (abstraction, attention, consciousness, logical reasoning, information-processing), which penetrated both the monastic and the humanist idea of the individual. Augustine’s ‘six ages’ of man gave the lifespan a fixed structure. Following the Reformation, change in the elect minority was seen either as instantaneous or as a stadial sequence: Jansenists and Calvinists on the one hand, Jesuits and Arminians on the other, disputed the function of human agency in relation to divine determinism.

This chapter begins with how Irenaeus, bishop of Lyons, brought the early traditions into a cohesive narrative whole by incorporating the abomination of desolation, the little horn, the fourth beast and the fourth king, the Man of Sin, the Son of Perdition, and the beasts that arose from the earth and the sea into the Antichrist figure. It then explores the development of the Irenaean story through Hippolytus of Rome, Tertullian, Lactantius, and Pseudo-Hippolytus. It analyses the various components of the story as they were developing over the third and fourth centuries, including the notion of double Antichrists, the role of Nero as the Antichrist, the Antichrist as Satan incarnate, and physical depictions of the Antichrist as a monstrous being in various Greek, Coptic, Syriac, Ethiopian, and Latin texts.

This chapter deals with the importance of the New Testament epistles of Paul, particularly Romans and Galatians, in the shaping of early Christian thinking on justification. After an initial overview of the wider importance of Paul, the emerging scholarly consensus that Paul was much more widely cited and used by early Christian writers than was thought a generation ago is explored. The chapter then focusses on three broad areas relating to justification in the pre-Augustinian tradition: the early phase from Irenaeus to Origen, the fourth century in the Greek East, and the fourth century in the Latin West, focussing particularly on Ambrosiaster. During the fourth century, the Pauline commentary emerged as a particularly important means of theological exploration and development in the Latin West, and had a clear impact on the consolidation of the western church’s theological vocabulary, particularly relating to justification. The chapter focusses particularly on how early Christian writers understood the Pauline phrase 'works of the law', noting that this was generally understood specifically in terms of the observance of the Mosaic law and its rituals. The way in which Paul's doctrine of justification by faith acts as a framework for discussing heilsgechichtliche issues – such as the faith of Abraham – is also noted.