And it came to pass, when Joab observed the city, that he assigned Uriah unto a place where he knew that valiant men were.

Wherefore as Joab was besieging the city, he put Urias in the place where he knew the bravest men were.

And it came to pass as Joab watched the city, that he assigned Urijah to a place where he knew that the valiant men were.

And it cometh to pass in Joab's watching of the city, that he appointeth Uriah unto the place where he knew that valiant men are;

So while Joab was watching the town, he put Uriah in the place where it was clear to him the best fighters were.

And so, when Joab was besieging the city, he positioned Uriah in the place where he knew the strongest men to be.

Observed the city - In the sense of besieging it closely.

And it came to pass, when Joab observed the city,.... Where lay its greatest strength, and where it was best defended; or besieged it, as the Targum:
that he assigned Uriah unto a place where he knew that valiant men were; who would not easily give way, and when they saw an opportunity would sally out, Joab cannot be excused from sin, unless he thought that Uriah had been guilty of death, and that David took this way of dispatching him for some political reason; however David was king, and to be obeyed.

The king's wishes were fully carried out by Joab. "When Joab watched (i.e., blockaded) the city, he stationed Uriah just where he knew that there were brave men" (in the city).