Moses, God forgave the people's sin of worshipping the calf. After
this was the feast of "Scenopegia" or of "Tents," which was kept for
seven days, to commemorate the blessing of being protected and led by
God through the desert, where they lived in tents. Hence during this
feast they had to take "the fruits of the fairest tree," i.e. the
citron, "and the trees of dense foliage" [*Douay and A. V. and R. V.
read: 'Boughs of thick trees'], i.e. the myrtle, which is fragrant,
"and the branches of palm-trees, and willows of the brook," which
retain their greenness a long time; and these are to be found in the
Land of promise; to signify that God had brought them through the
arid land of the wilderness to a land of delights. On the eighth day
another feast was observed, of "Assembly and Congregation," on which
the people collected the expenses necessary for the divine worship:
and it signified the uniting of the people and the peace granted to
them in the Land of promise.

The figurative reason for these feasts was that the continual
sacrifice of the lamb foreshadowed the perpetuity of Christ, Who is
the "Lamb of God," according to Heb. 13:8: "Jesus Christ yesterday
and today, and the same for ever." The Sabbath signified the
spiritual rest bestowed by Christ, as stated in Heb. 4. The Neomenia,
which is the beginning of the new moon, signified the enlightening of
the primitive Church by Christ's preaching and miracles. The feast of
Pentecost signified the Descent of the Holy Ghost on the apostles.
The feast of Trumpets signified the preaching of the apostles. The
feast of Expiation signified the cleansing of the Christian people
from sins: and the feast of Tabernacles signified their pilgrimage in
this world, wherein they walk by advancing in virtue. The feast of
Assembly or Congregation foreshadowed the assembly of the faithful in
the kingdom of heaven: wherefore this feast is described as "most
holy" (Lev. 23:36). These three feasts followed immediately on one
another, because those who expiate their vices should advance in
virtue, until they come to see God, as stated in Ps. 83:8.
________________________

FIFTH ARTICLE [I-II, Q. 102, Art. 5]

Whether There Can Be Any Suitable Cause for the Sacraments of the Old
Law?

Objection 1: It would seem that there can be no suitable cause for
the sacraments of the Old Law. Because those things that are done for
the purpose of divine worship should not be like the observances