59 So it was, on the eighth day, that they came to circumcise the child; and they would have called him by the name of his father, Zacharias. 60 His mother answered and said, "No; he shall be called John."  61 But they said to her, "There is no one among your relatives who is called by this name." 62 So they made signs to his father-what he would have him called.  63 And he asked for a writing tablet, and wrote, saying, "His name is John." So they all marveled. 64 Immediately his mouth was opened and his tongue loosed, and he spoke, praising God. 65 Then fear came on all who dwelt around them; and all these sayings were discussed throughout all the hill country of Judea. 66 And all those who heard them kept them in their hearts, saying, "What kind of child will this be?" And the hand of the Lord was with him.  Luke 1:59-66

The circumcision of a male child represented the admission of the child to the covenant relationship.  To read more about that, check out Leviticus 12:3.  It was a requirement of God, a "setting apart" if you will.  

There was speculation about the name after Elizabeth announced it.  Given names held a very important role in that culture (as they still do in some places), and since none of young John's relatives had carried that name before, his name was questioned.  It would seem that Zacharias was still struggling with the ability to speak, as he actually writes the child's name out on a tablet.

As soon as Zacharias writes out the name of his son, his tongue is loosed.  The first words that he uttered were words of praise to God.  Think about that for a moment; the last words he uttered BEFORE losing his speech were words of doubt.  The first words he utters when he receives it back are words of praise.  Apparently, his months of silence have been beneficial to him in the spiritual realm.  Sometimes, our silence can benefit us greatly, because in our silence we can sometimes hear the voice of God speaking to us.  

The scriptures tell us that Zacharias begins to prophesy after his tongue is loosed, and tomorrow we'll look at what he said.