Who's Your Mother?
Sibling rivalry is as old as dirt. All the way back in Genesis 3 we see the battle between the first set of brothers, Cain vs. Abel. In Genesis 21 there is another sibling rivalry. It involves the two sons of Abraham, Ishmael vs. Isaac. Paul uses the battle between these two siblings as an object lesson of a spiritual battle that can rage deep inside the soul of a believer.