The greatest question ever asked is in in the gospel of John ch 3. Jesus had just told a man that he needed to be born again! Then comes the great question "How can a man be born again, can he enter the 2nd time into his mothers womb and be born"? What a mind blowing question.
Jesus gave the answer "That which is born of the flesh is flesh, and that which is born of the spirit is spirit"?
The bible teaches us that the spirit and the flesh are constantly at war. Even the great Apostle Paul had to say that even after he had preached, he had to bring the flesh into subjection, lest he himself be lost.
The Christian life is a life of faith, in Jesus. Amen.