Three words. That is the entire text, and they are a complete Latin sentence doing three different grammatical jobs: is the imperative of donare, grant; is the dative of nos, to us; is the accusative of pax, peace. Command, indirect object, direct object - the skeleton of Latin syntax in one breath.
The words are the last petition of the Agnus Dei, sung in the Mass for over a thousand years. The round that carries them is younger and anonymous - tradition likes to blame Mozart, with no evidence - and it is the first canon most choirs on earth ever learn, because each voice sings the same easy line and the harmony assembles itself.
A pronunciation note for this course: the linked choir sings church Latin, where pacem is PAH-chem. Classical Latin, which our audio uses, would say PAH-kem. Both are real traditions; know which one you are hearing.