Luke 13:23

The narrow gate also represents the toils and sufferings of the saints. For as a victory in battle bears witness to the strength of the soldiers, so a courageous endurance of labours and temptations will make a man strong. Now our Lord does not seem to satisfy him who asked whether there are few that be saved, when He declares the way by which man may become righteous. But it must be observed, that it was our Saviour's custom to answer those who asked Him, not according as they might judge right, as often as they put to Him useless questions, but with regard to what might be profitable to His hearers. And what advantage would it have been to His hearers to know whether there should be many or few who would be saved. But it was more necessary to know the way by which man may come to salvation. Purposely then He says nothing in answer to the idle question, but turns His discourse to a more important subject.

This question seems to have reference to what had gone before. For in the parable which was given above, He had said, that the birds of the air rested on its branches, by which it might be supposed that there would be many who would obtain the rest of salvation. And because one had asked the question for all, the Lord does not answer him individually, as it follows, And he said unto them, Strive to enter in at the strait gate.