9 The true light, which enlightens everyone, was coming into the world. 10 He was in the world, and the world was made through him, yet the world did not know him. 11 He came to his own,  and his own people  did not receive him. 12 But to all who did receive him, who believed in his name, he gave the right to become children of God, 13 who were born, not of blood nor of the will of the flesh nor of the will of man, but of God.When I read this passage in Greek, something that struck me was that in verse 13
was that when it speaks of being born "not of the will of man" the word for "man" there wasn't anthropos, which denoted general mankind, but was actually aner, which was the masculine "man" opposed to "woman." It's used in verses like "each man ought to have his own wife." What always puzzled me about it was whether or not the "aner" had significance. After all, John had already spoken about not being born of the will of "flesh" which was the general word that John often used for humanity weakened by sin. It seemed redundant to speak of "flesh" and "man" separately.
Today, as I was listening to a sermon by R.C. Sproul on Genesis, I finally made a connection that makes sense!
Isaac wanted to bless Esau and not Jacob. Abraham thought he was going to bless Ishmael. In both cases, God wanted to bless another. Later on, Joseph wants Jacob to bless Manasseh and not Ephraim (Genesis 48). In all these cases, we discover that the promises are given not by blood, not of flesh, nor the will of the father, but by God.