Genesis 3:15, like much of the Bible, only seems to get deeper and deeper as time goes on. The offspring of the woman many agree refers to both Israel as a nation and the countless Christians that arose as a result of Jesus' ministry and the work of the 12 disciples upon the earth. We understand that this is yet another prophecy that has been, and continues to be fulfilled, but I believe it has yet another meaning.
 
   When Christians need to fight, whether it is when we are tempted by the things of the world (lust, greed, etc), Genesis 3:15 gives us a template and picture for how to fight. We should be as eagles, attacking the serpent in our terrain, throwing him in the air, rather than attempting to fight the serpent and his forces on the ground. We do not fight hate with hate, but hate with love. We do not fall to pride like our opponents, we stay humble and praise God for the victories in our lives. Similarly, when we are tempted by baser desires, we need to take flight like eagles. There's a reason why the Bible calls for us to flee from certain sins. Next time you're tempted, remember to take flight mentally. Engage the serpent in the air where he is weak, and crush his head instead of trying to wrestle him on the ground.
 
   The Bible talks about the reprobate mind. Those who have a reprobate mind cannot understand the things of God. They are too low, too carnal. Christians cannot have a reprobate mind, we are called to focus on the things in heaven, to go up higher with Him.
 
Supporting Verses
'Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things. ' -Philippians 4:8
 
' but those who hope in the Lord will renew their strength.They will soar on wings like eagles; they will run and not grow weary, they will walk and not be faint. '-Isaiah 40:31
 
' Set your minds on things above, not on earthly things. '-Colossians 3:2
 
' The woman was given the two wings of a great eagle, so that she might fly to the place prepared for her in the wilderness, where she would be taken care of for a time, times and half a time, out of the serpent’s reach. Then from his mouth the serpent spewed water like a river, to overtake the woman and sweep her away with the torrent. But the earth helped the woman by opening its mouth and swallowing the river that the dragon had spewed out of his mouth. Then the dragon was enraged at the woman and went off to wage war against the rest of her offspring—those who keep God’s commands and hold fast their testimony about Jesus. '-Revelation 12:14-17