Bhagavad Gita, Chapter 4, Verse 16

Even sages are bewildered, as to what is action and what is inaction. I shall therefore tell you what action is, by knowing which you will be freed from evil.

Even people who genuinely know a lot still get confused about what actually counts as real action versus real inaction.

This isn't a simple question with an obvious answer, Krishna admits upfront that even wise people struggle with it. That honesty is what makes the explanation that follows actually necessary, not just extra detail.