Jamieson, Fausset and Brown on Luke 13:25

25. master of the house is risen up and hath shut to the door--awfully sublime and vivid picture! At present he is represented as in a sitting posture, as if calmly looking on to see who will "strive," while entrance is practicable, and who will merely "seek" to enter in. But this is to have an end, by the great Master of the house Himself rising and shutting the door, after which there will be no admittance.

Lord, Lord--emphatic reduplication, expressive of the earnestness now felt, but too late. (See on Mt 7:21, 22).