In the dark they dig through houses, which they had marked for themselves in the daytime: they know not the light.
Dig through. Houses in the East are generally built of sun-dried mud bricks (so Matthew 6:19) х diorussousin (G1358)]. "Thieves break through" - literally, dig through (Ezekiel 12:7, "I digged through the wall with mine hand").
Had marked - rather, as in Job 9:7, 'They shut themselves up' (in their houses) - literally, they seal up.
For themselves - for their own ends, namely, to escape detection.
Know not - shun.