Vespers, or Evensong, is the Church’s evening prayer. It is very similar to Lauds, both in construction and in basic theme. The Church looks back on the day of salvation just passed with all its redeeming graces—and is fervently grateful. Vespers is a thanksgiving prayer. Thanksgiving is the principal theme: the Magnificat is the climax, the great thanksgiving song of the Church. The canonical-hour theme is this: thanks be to God for the day just passed, both in the soul and in the Church, thanks for all his saving graces.
There is also a theme from the story of salvation to be found in Vespers—the Last Supper. At the very same time that Vespers is prayed, Christ was seated with his apostles in the upper room. This gives Vespers a special connection with the holy Eucharist, and as a matter of fact, a great number of the Vesper psalms are Eucharistic songs or at least can easily be referred to the Eucharist. This is particularly true of the so-called Hallel psalms (Psalms 112-117), which were sung at the Last Supper, and the Gradual psalms (Psalms 119-131), which were procession songs for pilgrimages to the temple. The Last Supper is itself a symbol the heavenly banquet.
There is one big difference between Vespers and Lauds: whereas the psalms of Lauds are all specially chosen songs, the Vesper psalms merely follow a numerical sequence in the psalter. They are not a series of thanksgiving hymns exclusively, as perhaps we might have expected.
by Dr. Pius Parsch