John 3:8

Verse 8. The wind bloweth, &c. Nicodemus had objected to the doctrine because he did not understand how it could be. Jesus shows him that he ought not to reject it on that account, for he constantly believed things quite as difficult. It might appear incomprehensible, but it was to be judged of by its effects. As in this case of the wind, the effects were seen, the sound was heard, important changes were produced by it, trees and clouds were moved, yet the wind is not seen, nor do we know whence it comes, nor by what laws it is governed; so it is with the operations of the Spirit.