Translations
And it came to pass, when Joab observed the city, that he assigned Uriah unto a place where he knew that valiant men were.
When Yo'av was keeping watch against the city, he stationed Uriyah at the place where he knew the most capable men were.
As Joab kept watch on the city, he placed Uriah at the very position where he knew the fiercest enemy fighters would be.
So as Joab besieged the city, he assigned Uriah to a place where he knew the strongest enemy soldiers were.

