Galatians 3

Therefore know that only those who are of faith are sons of Abraham.  And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand, saying, “In you all the nations shall be blessed.” vv.7-8

Read chapter 3

Father Abraham had many sons, 

many sons had father Abraham, 

I am one of them and so are you, 

so lets all praise the Lord 

(right arm, left arm, right foot, left foot)

That's a song many of us may know from Sunday school when we were kids, but are those lyrics really true?  Is Abraham our "spiritual father"? Or what about the term "Spiritual Israel"?  It's a term we hear of sometimes in church, but what do people mean by it?  Is it something true? Are these ideas even described in the Bible for believers today?  Well people like to use this verse in Galatians chapter three to prove that once someone becomes a believer today they become a part of Israel.  BUT THIS IS NOT WHAT THIS VERSE IS SAYING.  Paul is writing to believing Jews in this letter to the Galatians.  He's telling them [Israelites] that they are true sons of Abraham if they showed faith, not just any person in the world can claim to be a child of Abraham if they have faith. My friends and Bible teachers Andy Brown and Nathan Johnson described this with metaphor that helps make more clear this for today: 

Suppose I should claim that only those who love their country to the extent that they would give everything up for it are worthy of being called “Americans.”  In the course of my argument, I declared, “All who love their country to the extent of giving up their lives for it if need be are true Americans.”  Now, someone living in Great Britain received a copy of my statement.  This person is a real patriot, and knows he would give up his life for his country if need be.  Therefore, he decides that, according to me, he must be a true American!  When another person argues with him that he cannot be a true American since he is not an American citizen but rather is British, he replies, “Well, Nathan must mean that I’m a ‘spiritual’ American!”  Would this be a correct interpretation of what I’d said?  Of course not!  The fact is that I was making my argument, not to people from Britain, but to my fellow Americans.  I meant that anyone who lives in the United States and meets the criteria I was promoting is a true American.  Although I did not state that condition, it should be clear to all who heard me that that is what I meant.  The man in Britain who read my statement must realize that he is not my intended audience. (www.precepts.wordpress.com)

In verse 8 Paul is further proving his point that if even the gentiles are bless by believing how much more so will believing Israelites.  So next time you hear the Father Abraham song or "spiritual Israel" (which isn't in scripture) remember that you are blessed to be a child of God because of your faith in Jesus Christ without being literal or spiritual Israel.