8 The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.” 9 Nicodemus said to him, “How can these things be?” 10 Jesus answered him, “Are you the teacher of Israel and yet you do not understand these things? 11 Truly, truly, I say to you, we speak of what we know, and bear witness to what we have seen, but you do not receive our testimony. 12 If I have told you earthly things and you do not believe, how can you believe if I tell you heavenly things? 13  No one has ascended into heaven except he who descended from heaven, the Son of Man. 14 And as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up, 15 that whoever believes in him may have eternal life. (John 3:8-15 – English Standard Version)

 
How do we know we are born of the Spirit?  There must be signs.  It should be reflected in our lives.  It should be physical that can be seen.  When the wind blows, we do not know where it comes from or where it goes, but we know it exists because the leaves move and we can feel the breeze.  We may not understand every work of the Spirit and we may not know where the Spirit is leading us, but we know it exists.  We can see the changes and we can feel the difference.  That is real.  We can be assured that the Spirit is in us.

 
“The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.”