en_tn_condensed/nam/03/14.md

Go draw water for the siege ... pick up the molds for the bricks

Nahum speaks to the people of Nineveh. He tells them to prepare for battle and to repair the walls, although he knows that the enemy will destroy the city.

strengthen your fortresses

"repair the fortifications"

go into the clay and tread the mortar; pick up the molds for the bricks

These phrases refer to making mud bricks that they will use to repair the city's wall.