Here are the main points of 115 - 121.
Notice the constant concern for the active participation of the congregation
- they are not to be just spectators.

116. The Church acknowledges Gregorian chant as specially suited to the Roman liturgy:
therefore, other things being equal, it should be given pride of place in liturgical services.
It is desirable also that an edition be prepared containing simpler melodies, for use in small churches.

118. Religious singing by the people is to be intelligently fostered
 so that the voices of the faithful may ring out

119. In certain parts of the world, especially mission lands,
there are peoples who have their own musical traditions.
Importance is to be attached to their music, and a suitable place is to be given to it

120. In the Latin Church the pipe organ is to be held in high esteem,
for it is the traditional musical instrument
which adds a wonderful splendor to the Church's ceremonies
and powerfully lifts up man's mind to God and to higher things.

But other instruments also may be admitted for use in divine worship
... on condition that the instruments are suitable for sacred use,
accord with the dignity of the temple,
and truly contribute to the edification of the faithful.

Let composers produce compositions which have the qualities proper to genuine sacred music,
not confining themselves to works which can be sung only by large choirs,
but providing also for the needs of small choirs
and for the active participation of the entire assembly of the faithful.

The texts intended to be sung must always be in conformity with Catholic doctrine;
indeed they should be drawn chiefly from holy scripture and from liturgical Sources

c.f. Psalms 149, 150

Sing a new song to the Lord.
Let the praise of God be always on our lips.

Praise God in his holy temple.
Praise him in the heavens.

O praise him with sound of trumpet.
Praise him with lute and harp.

Praise him with drums and dancing.
Praise him with strings and pipes.

Let everything that lives and breathes,
give praise to the Lord our Creator.  Alleluia!

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