"The Eucharistic assembly (synaxis), because the Eucharist is celebrated amid the assembly of the faithful, the visible expression of the Church."
Priests are supposed to celebrate mass every day, even if nobody's there.
Can. 906 A priest may not celebrate the eucharistic Sacrifice without the participation of at least one of the faithful, unless there is a good and reasonable cause for doing so
"The Eucharistic assembly (synaxis), because the Eucharist is celebrated amid the assembly of the faithful, the visible expression of the Church."
"Priests are supposed to celebrate mass every day, even if nobody's there."
The Holy Sacrifice of the Mass does require a congregation for validity or licitness. The efficacy of the representation of the sacrifice of Calvary in an unbloody manner is dependant upon the mass in and of itself - offered by a priest validly in Holy Orders, correct matter (unleavened bread and wine), and the correct sacramental intention of the priest.
The continual efforts of some liturgists to turn it into some sort of communal pagan meal, happy-slappy celebration of "community" goes against all Catholic notions of sacramental theology, the writisngs of the Fathers and Doctors of the Church, and of Sacred tradition itself.
A priest is to say mass everyday. If there is no mass with a congregation for him to say - or that is scheduled, then he says a private mass. He also may choose to offer a private mass for a special intention.
....all modernist ravings to the contrary!