Basics of New Testament Syntax, The Quotes

“Case is the inflectional variation in a noun7 that encompasses various syntactical functions or relationships to other words. Or, put more simply, case is a matter of form rather than function. Each case has one form but many functions.”
― Daniel B. Wallace, The Basics of New Testament Syntax: An Intermediate Greek Grammar

“In the eight-case system there is a tendency for precision of function while in the five-case system there is more room to see an author using a particular form to convey a fuller meaning than that of one function.”
― Daniel B. Wallace, The Basics of New Testament Syntax: An Intermediate Greek Grammar