en_tn_lite_do_not_use/jer/51/11.md

General Information:

Jeremiah is speaking to the people of Jerusalem as if he were speaking to the people of Babylon and their enemies, who cannot hear him, telling them that Yahweh will destroy Babylon before the Babylonians can prepare to defend themselves. (See: rc://en/ta/man/translate/figs-apostrophe)

Lift up a banner over Babylon's walls

"Give a signal to attack Babylon's walls"

make the watch strong

"make sure the guards are strong and have good weapons"

set up watchmen

"make sure there are enough men watching the city"

prepare the ambushes

This was done in order to catch anyone running from the city.