Here "spirit" represents a person's inner being. Alternate translation: "Those who are wrong in what they think" or "Those who are wrong in their attitude" (See: [[rc://en/ta/man/translate/figs-metonymy]])
This can be made more explicit to explain what they will understand. Alternate translation: "will begin to understand Yahweh and his laws" (See: [[rc://en/ta/man/translate/figs-explicit]])
This can be made more explicit to explain what knowledge they will learn. Alternate translation: "those who complain will begin to know that what Yahweh teaches them is true" (See: [[rc://en/ta/man/translate/figs-explicit]])