Listen, even though you do not understand this. The sound of the wind is also heard in this Word of God: "I baptize you in the name of the Father and of the Son and of the Holy Spirit." Furthermore, you also have the wind in the baptismal water; the Holy Spirit is blowing there. You cannot understand how a man can be renewed by water and the Holy Spirit, nor how one who has died can live anew. But believe it, accept it, and content yourself with hearing the sound of the water and with feeling the water and the the sound of the Holy Spirit. It matters not that you cannot understand how you are renewed. Just say: "I will believe it. I do not know either whence the wind comes; and still I know that it exists, for I can hear and feel it. Thus I will also believe God when He says that Baptism initiates a new birth, even though I cannot understand how it can renew me, keep and preserve me for eternal life. I will simply hear the Word, accept the water of Baptism, and believe. After all, I have to accept far lesser things without understanding them. The fact that I was born anew this way is just as true as the fact that I hear the word. Just as I know that I hear and feel the wind but do not know whence it comes, so I shall also believe that I am born anew by water and the Holy Spirit and that the old man in me must die if I wish to enter eternal life."
LW AE vol 22 p 295
Sermons on St. John, 1539