The Introit is a call to prayer, yes, but a call to prayer followed by Catholic Action. It bespeaks “the voice of joy,” yes, but also counsels “clap your hands,” which in ancient times signified not only to praise a person by the tongue but to work for him with the hands. Since if all the tree’s life goes into the wagging tongues of waving leaves, how can there be any fruit?
Deeds, not mere words, are acceptable to God and are the best kind of example to neighbour. “The fruit” of sin is shame and death (Epistle), while the fruit of sanctity is life everlasting. “By their fruits” shall you know false teachers of false Christians (Gospel).
Not so much what one “says” about the Lord, but he who “does” His Will, brings forth good fruit. The Holy Eucharist is the “health giving” (Postcommunion) fruit of Calvary, to counteract the poison laden “Dead Sea” fruit of the world.