Ethos

The Articles of Confederation was a legal document designed to prevent government tyranny. No fat-cat monarchs allowed, basically. As such, the laws contain an appeal to Enlightenment ethical ideas.

For example, Article 3 promises that the government will provide for "common defense, the security of their liberties, and their mutual and general welfare" (3.1). These prescriptions are straight out of John Locke's social contract theory. Locke, a big influence on American thinkers like Thomas Jefferson, believed that the role of government was to protect the safety and wellbeing of citizens while respecting their natural rights. (Source)

Also pay attention to how the above sentence uses a kind of list format to enumerate, or name, the powers and purpose of the government. The "list" rhetoric of the Articles often shines through in the form of anaphora, or repetition of words. For example, check out the entirety of Article 6. Just about every sentence in this section belongs with "no state," causing the writing to take on a repetitive—but clear—structure.

It's sort of like a Buzzfeed listicle (7 Crazy Powers of the Confederation Congress!). This language reflects the goal of specificity and objectivity, both considered characteristics of ethical rhetoric.

The introduction and conclusion to the document also say that the delegates are acting in accordance with God's wishes, reinforcing the document's claim to moral legitimacy. "It hath pleased the Great Governor of the World to incline the hearts of the legislatures […] to approve of, and to authorize us to ratify the said Articles of Confederation and perpetual Union" (13.3).

In other words, God told them to sign this document. As far as ethics go, there was no higher authority for the colonists than the Almighty. Remember, this was before the 1st Amendment was a thing, so the phrase "separation of church and state" hadn't quite made it into the national playbook.