“Pharaoh called for Moses and Aaron, and said: Entreat the Lord, and He will remove the frogs from me, and from my people; and I will let the people go, and they will sacrifice to the Lord. Moses said to Pharaoh: Have this glory over me; for what time shall I entreat for you, for your servants, and for your people, so that the frogs will be destroyed from you and you houses, and will remain only in the Nile?” (Exodus 8:4–5).
“Pharaoh called” – when the punishment began in his body, he felt it immediately and began screaming: “Entreat the Lord, and He will remove the frogs…” “Moses said… and will remain only in the Nile” – all of them will die, and the only ones remaining will be those remaining in the Nile. “He said: For tomorrow” (Exodus 8:6) – from here you learn that this was the day that the seven days would conclude.
Therefore, Moses said to him: “For what time shall I entreat for you?” – for tomorrow I will entreat for you, but not for today; [and only then,] “the frogs will depart from you” (Exodus 8:7).