The mystery of the Church

“This mystery is that through the gospel the Gentiles are heirs together with Israel, members together of one body, and sharers together in the promise in Christ Jesus.” Ephesians 3:6
In Ephesians, Paul elaborates on the ‘mystery’ of the Church, the body of Christ. A ‘mystery’ in this sense is something that has not been revealed, until now. The mystery is not that Gentiles can be saved. This happened on many occasions in the Old Testament: Rahab, Ruth, and so forth – even Abraham was technically a ‘Gentile’ when he was declared righteous (see Rom. 4:9-10). However, under the Old Testament, a Gentile seeking to come to God had to proselyte into Judaism first. But even then, they could not enter the temple past the court of the Gentiles.
This is not the case in the body of Christ. As we read earlier in Gal. 2:28, we are now one in Christ. Jews and Gentiles have equal standing before God, and we are ‘heirs together’. In the body of Christ, there is no need for Gentiles to become Jewish in order to come to God. This was a big shake-up for the early church – and its something that some believers still struggle with today.