* The phrase "fear of Yahweh," and related terms "fear of God" and "fear of the Lord," refer to deeply respecting God and showing that respect by obeying him. This fear is motivated by knowing that God is holy and hates sin.
* Depending on the context, "to fear" can be translated as "to be afraid" or "to deeply respect" or "to revere" or "to be in awe of."
* The term "afraid" could be translated as "terrified" or "scared" or "fearful."
* The sentence, "The fear of God fell on all of them" could be translated as, "Suddenly they all felt a deep awe and respect for God" or "Immediately, they all felt very amazed and revered God deeply" or "Right then, they all felt very afraid of God (because of his great power)."
* The phrase "fear not" could also be translated as, "do not be afraid" or "stop being afraid."
* Note that the phrase "fear of Yahweh" does not occur in the New Testament. The phrase "fear of the Lord" or "fear of the Lord God" would be used instead.