we are all born into this world by natural birth and are all destined for hell because of the sin of Adam. If God had not chosen some to give eternal life to by the sacrifice of Christ, all mankind would burn in hell. In our natural state of being, we would never have the ability to understand spiritual things, according to 1 Cor 2;16 , so then, we could never be converted without understanding spiritual things, unless God first gave us new life by putting his Spirit within us ( regeneration ).