Drawing on recent insights into textual authority, this article examines how the authoritativeness of the Jewish scriptures is manifested in 1 Clement. The article argues that the relationship between the letter and the writings it uses in its argumentation should be seen as a two-way process of mutual authorisation. Moreover, the article illuminates the interrelatedness of textual authority, scriptural argumentation and the legitimation of leadership and power. Thus, the analysis both contributes to ongoing scholarly discussions of scriptural authority and highlights the role of scriptural argumentation in the identity-building of early Christians.

The article reopens the dossier of the sources, parallels and rewritings of 1 Cor 2.9, a saying that Paul attributes to a written source, when other sources put it into Jesus' mouth (e.g. GosThom 17). The state of research shows that the hypothesis of an oral source is generally preferred but an accurate study of 1 Clem 34.8, a parallel too often neglected, supports the presence of a written source that existed before 1 Cor 2.9. GosJud 47.10–13 will help to understand the attribution of the saying to Jesus. Finally, the article takes into account the well-known parallel in Islamic tradition, a ḥadīth qudsī.

In 1 Clement 32–33, Romans 5–6 is alluded to in a summary statement concerning justification by faith (32.4), followed by two rhetorical questions that stress the ethical implications of this confession (33.1). These allusions to Romans are punctuated by an appeal for readers to imitate the pattern of good works established by God during creation (33.2-8). This article contends that the difference between Romans 5–6 and one of the earliest Christian readings of these chapters is not accidental, for the ethical appeal in 1 Clement 33 reflects the author's distinct cosmological perspective and rhetorical aims.