# Israel attacked

Here "Israel" refers to the people of Israel. Alternate translation: "The Israelites attacked" 

# with the edge of the sword

"with the sharp part of the sword." or "and completely defeated them."  The "edge of the sword" is associated with death and complete destruction.

# took their land

"conquered the land of the Amorites." Here the word "their" refers to the Amorites.

# was fortified

"was strongly defended." The Israelites did not attack the Ammonites.