When does a believer become an heir with God and with Christ?
Scripture teaches that at the moment a person becomes a believer, they are immediately placed as an heir with the Father and the Son, without years of tutoring or training. This adoption is by Jesus Christ according to the good pleasure of His will, making them a joint heir from day one.
Les explains that in Roman and Greek culture, a child was put under tutors, educated and trained, and then went through the rites of adoption to come in at an equal level with the father. The Hebrew culture had something akin to this in the Bar Mitzvah at age 14. But Paul teaches that the moment we become a believer, we do not go through years of tutoring and training; we are immediately placed as an heir with the Father and the Son. This was the predestination—not to heaven or hell, but as a believer to that position with Christ from day one, as a joint heir in the process of the adoption. Ephesians 1:11 also speaks of obtaining an inheritance, being joint heirs with Christ.
Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will,