In the dark they dig through houses - This refers, probably, to another class of wicked persons. The adulterer steals forth in the night, but it is not his way to “dig” into houses. But the persons here referred to are robbers, who conceal themselves by day, and who at night secretly enter houses for plunder. The phrase “dig through” probably has reference to the fact that houses were made of clay, or of bricks dried in the sun - a species of mud cottages, and whose walls, therefore, could be easily penetrated. In the East, nearly all the houses are made of unburned brick, and there is little difficulty in making a hole in the wall large enough to admit the human body; compare Ezekiel 12:7. In Bengal, says Mr. Ward, it is common for thieves to dig through the walls of houses made of mud, or under the house floors, which are made merely of earth, and enter thus into the dwellings while the inmates are asleep. Rosenmuller’s Alte u. neue Morgenland “in loc.”
Which they had marked for themselves in the day-time - According to this translation the idea would be, that in the day-time they carefully observed houses, and saw where an entrance might be effected. But this interpretation seems contrary to the general sense of the passage. It is said that they avoid the light, and that the night is the time for accomplishing their purposes. Probably, therefore, the meaning of this passage is, “in the day time they shut themselves up.” So it is rendered by Gesenius, Rosenmuller, Noyes, and others. The word here used, and rendered “marked” (חתם châtham), means to seal, to seal up; and hence, the idea of shutting up, or making fast; see Job 9:7, note; Isaiah 8:17, note. Hence, it may mean to shut up close as if one was locked in; and the idea here is, that in the day-time they shut themselves up close in their places of concealment, and went forth to their depredations in the night.
They know not the light - They do not see the light. They do all their work in the dark.