Matthew 7:12

Before its first sentence finishes describing the Way of Life as love of God and neighbor, the Didache states this same principle in a different shape: whatever a person would not want done to himself, he should not do to another. That is the negative form, structurally the same maxim Confucius gives his student Tsze-kung under the name reciprocity, recorded in the Analects (15.24). Matthew states the rule positively, do to others what you would have them do to you, and the two forms are not the same claim; the negative version only forbids harm, while the positive version obligates active kindness a person might not otherwise have thought to extend.

That the Didache preserves the negative form in its own opening catechetical section, independent of quoting Matthew's Gospel directly, suggests the maxim was already circulating in early Christian teaching in more than one wording before any single Gospel text fixed it. Whether the Didache drew the line from a source earlier than Matthew or simply preserved a popular ethical commonplace already old by the first century is not settled by the text itself, but the coexistence of both forms in the earliest Christian literature is evidence that neither wording had yet become the only one.