Was it the second prophecy in the Bible, after the prophecy of death for eating the fruit? In this one, it is stating there would be a perpetual struggle going on between demonic forces, which would include the devil's servants among man, and mankind. Satan would deal a crippling blow to mankind by wounding the heel, but Satan's kingdom would be destroyed, get a fatal head wound. The bruising of the heel has ultimately to do with Christ being crucified, wounded but not defeated, overcoming death and victorious, a wound of the heel not of devastating nature, while Satan's wound will be a head wound, devastating to Satan and his kingdom. Or, Satan wounds Christ's heel, Christ wounds Satan's head, the latter the much worse for wear, Christ's head intact, but not Satan's. Interesting there's a mortal beast related head wound in Revelation, also, the beast or antichrist Satan's Messiah knockoff.