Sit not down (μη κατακλιθηις). First aorist (ingressive) passive subjunctive of κατακλινω, to recline. Old verb, but peculiar to Luke in the N.T. (Luke 7:36; Luke 9:14; Luke 14:8; Luke 24:30).

Be bidden (η κεκλημενος). Periphrastic perfect passive subjunctive of καλεω after μη ποτε.