Our understanding of the importance of John the Baptist is highlighted in the fact that he is one of one three whose birth and death are celebrated by the Church - Jesus, Mary and John. It is usual for the Church to recognize the entry into heaven that comes with death, since this is the new birth of the saints in glory, but in these three we celebrate both.
I found that the Preface for this Solemnity of the Nativity of Saint John the Baptist states so well the high regard we have for this saint. I would like to share these words with you that come from the Roman Missal.
"It is truly right and just, our duty and our salvation,
always and everywhere to give you thanks,
Lord, holy Father, almighty and eternal God,
through Christ our Lord.
In his Precursor, Saint John the Baptist,
we praise your great glory,
for you consecrated him for a singular honor
among those born of women.
His birth brought great rejoicing;
even in the womb he leapt for joy
at the coming of human salvation.
He alone of all the prophets
pointed out the Lamb of redemption.
And to make holy the flowing waters,
he baptized the very author of Baptism
and was privileged to bear him supreme witness
by the shedding of his blood.
And so, with the Powers of heaven,
we worship you constantly on earth,
and before your majesty
without end we acclaim ... "