On The Holy Trinity by St. Augustine
Chapter 5.--The Number Six is Also Commended in the Building Up of the Body of Christ and of the Temple at Jerusalem.
9. And not without reason is the number six understood to be put for a year in the building up of the body of the Lord, as a figure of which He said that He would raise up in three days the temple destroyed by the Jews. For they said, |Forty and six years was this temple in building.| And six times forty-six makes two hundred and seventy-six. And this number of days completes nine months and six days, which are reckoned, as it were, ten months for the travail of women; not because all come to the sixth day after the ninth month, but because the perfection itself of the body of the Lord is found to have been brought in so many days to the birth, as the authority of the church maintains upon the tradition of the elders. For He is believed to have been conceived on the 25th of March, upon which day also He suffered; so the womb of the Virgin, in which He was conceived, where no one of mortals was begotten, corresponds to the new grave in which He was buried, wherein was never man laid, neither before nor since. But He was born, according to tradition, upon December the 25th. If, then you reckon from that day to this you find two hundred and seventy-six days which is forty-six times six. And in this number of years the temple was built, because in that number of sixes the body of the Lord was perfected; which being destroyed by the suffering of death, He raised again on the third day. For |He spake this of the temple of His body,| as is declared by the most clear and solid testimony of the Gospel; where He said, |For as Jonas was three days and three nights in the whale's belly, so shall the Son of man be three days and three nights in the heart of the earth.|