The phrase "择善固执" is formed by combining two distinct grammatical constructs from classical Chinese: the first two characters, "择善", create a verb-object phrase meaning "to choose good", and the last two, "固执", form an adverb-verb phrase meaning "to hold firmly". When concatenated, they produce a compound idiom that literally conveys "to choose good and hold to it firmly", illustrating a conceptual unity through sequential actions.