The delights of the gerundive of obligation

Chef: Slave! This dish is to be taken to table 4.

coquus: serve! haec patella ad mensam quartam portanda est.

The gerundive is really the future passive participle. Because the future indicative is very concrete in Latin (otherwise the present subjunctive would be used), a future participle implies that the event is DEFINITELY going to happen and therefore MUST happen – hence the gerundive of OBLIGATION.

is to be i.e. must be
is to be i.e. must be
is to be i.e. must be

1.) puella amanda est.
2.) hostis vincendus est.
3.) vinum bibendum est.
4.) legiones vocandae sunt.
5.) pecunia non rapienda est.

The agent (by whom the action must be done) will be in the DATIVE.

1.) consuli senatus convocandus est.
2.) coquis cenae parandae sunt.
3.) ianua ianitori aperienda est.
4.) multa facienda sunt mihi.
5.) nobis voces feminae cantantium audiendae sunt.

Remember that the gerundive of obligation might appear in an indirect statement (the cook says that the dish is to be taken to table 4). As one would (or should!) expect, the gerundive is coupled with the INFINITIVE (since it forms part of the accusative and infinitive construction).

coquus dixit patellam ad mensam quartam portandam esse.