The Symbology of Numbers

1 the Undivided Oneness of God
2 the two natures of Christ; both the Divine and the material
3 the Three Persons of the Most Holy Trinity, the three Magi and their gifts
4 the Evangelists and their Gospels; the elements, humors and material world; North, South, East, and West; the four seasons
5 the Five Wounds; the senses
6 the days of creation; creation fallen; imperfection
7 covenant, oath; perfection; the day God rested (the Sabbath being the sign of the Covenant with Adam); the seven colors the rainbow (a sign of the Covenant made with Noe); the seven Sacraments (the Covenant sign made with the Church); the Gifts of the Holy Ghost; the virtues and vices
8 the visible world, made in seven days, with the invisible kingdom of grace following; regeneration
9 man's imperfection; the choirs of Angels
10 the Commandments; the Plagues of Egypt
12 the tribes of Israel; the Apostles; the signs of the Zodiac; the hours of the day and the hours of the night; the penetration of matter with spirit (3 X 4)
13 betrayal; Judas
33 the number of years of Jesus's human life
40 testing and trial; the years of the Deluge; the years of wandering in the desert in Exodus; the days Moses spent on Mt. Sinai; Christ's days in the desert
666 the number of the Beast. (Also 616 in some later manuscripts, a number rejected by St. Irenaeas as a scribal error).
1000 the milennium -- the Church Age