We had a guest preacher today: Mark Mullery. He preached the final message for The Atonement series on Adoption. It was an excellent message, entitled "Sons of God and God the Son" from Galatians 4:4-7 (sermon audio).
After the message, I went up to ask him about the nature of our inheritance as believers. He said that, first, God has given the Spirit of Christ to us as a deposit, guaranteeing the inheritance (2 Corinthians 1:22; 2 Corinthians 5:5; Ephesians 1:14). Second, we will dwell in new bodies in a new earth with new heavens.
I've been thinking about Romans 8:17 for awhile, and what it means when it says we are "heirs of God," so I asked him what it meant. He said that the word of is ambiguous and can be either an objective genitive or a subjective genitive.
Remember, a genitive is a word expressing possession. An objective genitive serves to indicate the object of possession, and a subjective genitive serves to indicate the source (or origin) of possession. Therefore, if "heirs of God" indicates objective possession, then God Himself is the inheritance. If, however, it indicates subjective possession, then God Himself is the source of other things to be inherited.
Mark said he thinks that the ambiguity is intentional. In other words, God Himself and other things (new body, new heavens, new earth) are the inheritance of the believer.
