en_tn/2sa/16/23.md

Now the advice of Ahithophel ... was as if a man heard

Here the author compare how much people trusted Ahithophel's advice with how much they would trust advice directly from God. Alternate translation: "Now people trusted the advice of Ahithophel in those days in the same way they would have trusted it if had come" (See: rc://en/ta/man/translate/figs-simile)

as if a man heard from the mouth of God himself

Here God's mouth represents himself and emphasizes his speech. Alternate translation: "as if God had said it with his own mouth" or "as if a man heard it spoken by God himself" (See: rc://en/ta/man/translate/figs-synecdoche and rc://en/ta/man/translate/figs-rpronouns)

all of Ahithophel's advice was viewed by both David and Absalom

This can be translated in active form. Alternate translation: "both David and Absalom viewed all of Ahithophel's advice"

was viewed

"was thought of"