Longsuffering should not be confused with unconditional.
Just ask Dan.
Israel's choosing by God is mirrored in the Church as a whole being chosen and predestined by God. Just as there were individuals lost that belonged of Israel, there will be individuals who will lose out that were once in church.
But you are right.. we are hijacking this thread.
Last response belongs to you:
The OT is certainly an historical document but it is full of types and shadows. It speaks to our experience as individuals as much as it does the church as a whole. The experience of the nation of Israel is a type of the individual's experience in the NT experience.
In addition I'd offer that the NT commentary certainly should influence our approach to the NT and not the other way around. This is a product of the dispensation of revelation - particularly in the words of Christ and the Apostles. Both of which clearly reflect more than a long-suffering God but instead of loving, jealous and protective Father.