John 3:4

πῶς δύναται ἄνθρωπος γεννηθῆναι γέρων ὤν; μὴ δύναται, etc. In this reply there is no attempt to fence with Jesus, but merely an expression of the bewilderment created by His statement. The emphasis is on πῶς, which asks for further explanation. The μὴ of the second clause shows that Nicodemus understood that Jesus could not mean a second physical birth (see Lücke). On γέρων ὤν Grotius remarks: “Exemplum in se ponit, qui senex jam erat”. That our Lord understood Nicodemus' words as a request for further explanation appears from His at once proceeding to give it.