Charles Ellicott Commentary Esther 5:9

"Then went Haman forth that day joyful and glad of heart: but when Haman saw Mordecai in the king`s gate, that he stood not up nor moved for him, he was filled with wrath against Mordecai." — Esther 5:9 (ASV)

He stood not up. — In Esther 3:2, we saw that Mordecai refused to bow or prostrate himself to Haman; here, he refuses even the slightest sign of respect. The honourable independence of the former case here becomes indefensible rudeness.