A.T. Robertson Commentary Luke 13:28

"There shall be the weeping and the gnashing of teeth, when ye shall see Abraham, and Isaac, and Jacob, and all the prophets, in the kingdom of God, and yourselves cast forth without." — Luke 13:28 (ASV)

There (εκε). Out there, outside the house whence they are driven.

When ye shall see (οταν οψησθε). First aorist middle subjunctive (of a late aorist ωψαμην) of οραω, though οψεσθε (future middle) in margin of Westcott and Hort, unless we admit here a "future" subjunctive like Byzantine Greek (after Latin).

And yourselves cast forth without (υμας δε εκβαλλομενους εξω). Present passive participle, continuous action, "you being cast out" with the door shut. See on Mt 8:11f. for this same picture.