"They who know the truth are not equal to those who love it, and they who love it are not equal to those who delight in it." I can see the most straightforward interpretation of it's first two parts but I am unsure of the third.
Interesting quote, I have never encountered it. Before my interpretation, an important note should be made which is that the translation of the quote may be causing the Confucian and that there may be multiple or better translations (this is common for old quotes). Because of this, in this translation, I believe the terms "love" and "delight" should be switched.
With that being said, I believe it goes into the idea of truth for the sake of truth. In this context, for example, those who "love" the truth do so for the shallow reasons such as how it is consequentially useful. However, those who "delight" in the truth do so in appreciation of knowledge.