For the stone shall cry out of the wall, and the beam out of the timber shall answer it.
For the stone shall cry out of the wall. Personification. The very stones of thy palace, built by rapine, shall testify against thee (Luke 19:40).
And the beam out of the timber - the cross-beam or main rafter connecting the timbers in the walls.
Shall answer it - "it," namely, the stone. The stone shall begin, and the cross-beam continue the cry against thy rapine.