The Fullness of the Gentiles

Though some translations say it's the "full number of Gentiles"  who are to come in before all Israel is saved, "the fullness of the Gentiles"  is more accurate (Romans 11:25/26).  If Paul had simply wanted to speak of the salvation of a certain number of Gentiles, he'd have used the Greek word 'arithmou'.  Instead, he used the word 'pleroma'  to speak of something that is complete, as well as being a mystery to be understood (v25).

This 'completeness' is therefore the jump-start for the saving of all Israel, that leads to the end of the present age.  The clue to what will constitute it coming in how Jesus spoke of the signs of the end, referring to both 'the times' and the 'Gentiles' when He said Jerusalem would be trampled on by the Gentiles "until the times of the Gentiles are fulfilled"  (Luke 21:24).

In Hebrew the word 'goy' (= Gentile) can mean a nation or a people, but also mean 'heathen' in an almost derogatory way.  If taken in this sense the catalyst for the saving of all Israel is then the full iniquity of the heathen when God lifts His hand of restraint (2 Thessalonians 2:6), having given the Gentiles time to repent during the "partial hardening" of Israel (Romans 11:25).  In which case, today's unprecedented rise of wickedness suggests it's getting near.

"They have made me jealous by what is no god ... I will make them jealous by those who are not a people!" (Deuteronomy 32:21)

If so, this means the opportunity has largely passed for the Gentiles to "make Israel jealous"  (Romans 11:11), because the Church's testimony has been so compromised through history, and its portrayal of Jesus so Gentilised, He's as unrecognisable to Jewish people as Joseph was to his Jewish brothers.

Which now puts the onus onto Messianic believers to make their own people jealous and onto us to fully support them as they do so,  whilst we express the fullness that comes from our being 'grafted in'.