Who ridiculed the builders before the army of Samaria, asking, "What are these feeble Jews doing?"

Answer: Sanballat

Furious at the rebuilding, Sanballat mocked the Jews; then Tobiah the Ammonite added that even a fox would break down their wall.

“Now when Sanballat heard that we were rebuilding the wall, he was furious and filled with indignation. He ridiculed the Jews”— Nehemiah 4:1 (BSB)