They which are the children of the flesh, these [are] not the children of God: but the children of the promise are counted for the seed. Romans 9:8
I was not good at math. Understatement--I flunked algebra two years in a row. I think I balanced an equation once, but soon the figures became meaningless to me. Like a bunch of ants marching on a text book page. Of course I find ants interesting.
Later, in college, I was introduced to the diagrams of John Venn which he introduced about 1830. (I just looked them up.) Now I began to understand a little. They helped a lot.
Some time ago I told of Charles the cleaning man. He was wrestling with the quotation which says "all Israel shall be saved" (Romans 11:26). It was a mystery to us both, for we knew there were lost Israelites, like Judas.
Now I will try to use Venn to illustrate this idea. On a blank sheet of paper I draw a square. I will label the square "All People". Inside the square I make a circle and call it "Israel". Finally I draw a circle and call it "Children of Promise". Only this circle overlaps the Israel circle a bit.
Where the two circles intersect, we have "Israel of God". These are God's people, who he fore ordained, believing Israelites, or "all Israel".
Does this work? I hope this illustration is correct. I flunked math, but I want to get this one right.