Charles Ellicott Commentary Esther 5:4

"And Esther said, If it seem good unto the king, let the king and Haman come this day unto the banquet that I have prepared for him." — Esther 5:4 (ASV)

Let the king and Haman come this day unto the banquet. —It was natural enough that, with so much depending on her request, the queen should show some hesitation: if anything took an unfavorable turn (for, in spite of the king’s promise, she evidently felt uneasy) it might mean total ruin. She therefore temporizes; she at any rate gains time and secures a specially favorable opportunity for bringing forward the request, and the king clearly sees that she has kept her real petition in reserve by his own raising the question again.

It will be noticed that as long as Esther is working her way up to the due vantage point, the king is addressed in the third person, let the king come, but when she makes the decisive appeal, in the second person, in thy sight, O king.