en_tn_condensed/act/04/25.md

You spoke by the Holy Spirit through the mouth of your servant, our father David

This means that the Holy Spirit caused David to speak or write down what God said.

through the mouth of your servant, our father David

Here the word "mouth" refers to the words that David spoke or wrote down. Alternate translation: "by the words of your servant, our father David" (See: rc://en/ta/man/translate/figs-metonymy)

our father David

Here "father" refers to "ancestor/"

Why did the Gentile nations rage, and the peoples imagine useless things?

This is a rhetorical question that emphasizes the futility of opposing God. Alternate translation: "The Gentile nations should not have raged, and the peoples should not have imagined useless things" (See: rc://en/ta/man/translate/figs-rquestion)

the peoples imagine useless things

These "useless things" consist of plans to oppose God. Alternate translation: "the peoples imagine useless things against God" (See: rc://en/ta/man/translate/figs-explicit)

peoples

people groups