A psalm is
a blessing on the lips of the people,
a hymn in praise of God,
the assembly’s homage,
a general acclamation,
a word that speaks for all,
the voice of the Church,
a confession of faith in song.
It is the voice of complete assent,
the joy of freedom,
a cry of happiness,
the echo of gladness.
It soothes the temper,
distracts from care,
lightens the burden of sorrow.
–St. Ambrose of Milan (339-397)