Nicodemus is “born of the flesh.” Like us, therefore, he tends to think in fleshly ways – even when trying to understand the spiritual world. When Jesus requires a new birth, Nicodemus thinks of a second physical birth. So Jesus repeats His requirement in a way Nicodemus might recognize:
Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God (John 3:5).
John the Baptizer uses “water” while promising “the kingdom of God.” Jesus also requires water. But what about “Spirit”? Is this a second event, as if one must be born “of water,” and at another time “of Spirit”?
In any case, we have no power over the Spirit. We could not even do the smaller thing of choosing our first birth and our fleshly parents. How can Jesus make “birth” a command for us, and hold us responsible?