The Scottish Parliament that met in August 1560, with the regent Mary of Guise dead two months and Catholic establishment in Scotland effectively at an end, ordered six ministers, John Knox among them, to draw up a confession of the reformed faith. Knox's own account says they did it in four days. The speed shows in the text: it is direct, argued in the first person plural as we believe and we confess, and carries a polemical energy that the later and more measured confessions generally lack.
Its twenty-five chapters move from the nature of God and original sin through Christ, election, the church and the sacraments to civil authority, and chapter eighteen, on the notes by which the true kirk is discerned from the false, states a concern shaped directly by Scotland's recent break with Rome: true doctrine rightly preached, the sacraments rightly administered, and ecclesiastical discipline uprightly ministered. Parliament ratified the confession within days of receiving it, and in the same short session abolished papal jurisdiction in Scotland and forbade the mass, so the document arrived as one part of a single legislative act of national religious change rather than as a standalone theological statement.
Knox and his colleagues wrote knowing the political window might close as fast as it had opened. The confession's urgency is that of a church establishing itself before the settlement could be reversed, and the fear was not idle: Mary, Queen of Scots returned from France the following year and heard mass in her own chapel over the Kirk's protest.