The default translations work most of the time — like “of” for the genitive. But many times, “of” just doesn't make sense, and that is when you need to check the advanced uses of a case. Here is an example of what is called a “genitive of apposition,” #16.21 in Greek for the Rest of Us.

One of the more common constructions in Greek is the appositional construction. It is often downplayed in first–year Greek, but it is quite common. There are also two types of appositional constructions, the Simple Apposition and the Genitive of Apposition. The difference between the two is nuanced but important. We will be looking at three verses, Ephesians 1:1, 1 John 1:3, and Romans 4:11.

Sometimes translators have to make a decision; sometimes there is no ambiguous option. In 2 Cor 4:6, is the gospel glorious or is the gospel about the glory of Christ? It is one or the other, not both.

The KJV gives us an unfortunate translation of the genitive in Galatians 2:7, which can be easily misunderstood as teaching that there are two different gospels. One gospel is for the Gentiles, while the second gospel is for the Jews. Speaking of the leaders of the Jerusalem Church, he says, “They saw that the gospel of the uncircumcision (τὸ εὐαγγέλιον τῆς ἀκροβυστίας) was committed unto me, as the gospel of the circumcision (τῆς περιτομῆς) was unto Peter.” (τὸ εὐαγγέλιον is assumed from the previous phrase.)

Sometimes the translator just has to make an interpretive decision. The Greek can mean one thing or something else, and you have to choose. Hebraic (or attributive) genitives often force this type of decision. 2 Corinthians 4:4.

This is a rather technical blog on the nature of Greek appositional constructions. I imagine I lost many of you with that first sentence, but the distinction between the two forms is important exegetically. If you read "x of y," is "y" the same thing as "x" or is "y" explaining something about "x"?