Or HaChaim on Exodus 9:30/אור החיים על שמות ט׳:ל׳

1 ואתה ועבדיך, "for both you as well as your servants, etc." Moses mentioned the servants because he saw that they too had not paid heed to G'd's warning and had left their livestock outdoors together with their shepherds. Should you query this by asking how did Moses know this, seeing the servants had accepted G'd's judgment when Pharaoh said: "G'd is righteous whereas I and my people are the evildoers," remember that I have explained that G'd had already revealed His intention to bring on the plague of killing the Egyptians' firstborn. He had also warned in 7,4 that Pharaoh would not listen to Moses and Aaron. As a result, Moses was entitled to consider all the protestations of Pharaoh that he addmitted being a sinner, etc. as being merely a maneuver to gain time. If Pharaoh and his servants had truly repented it is hardly likely that G'd would punish them by the plague of killing the firstborn. Moses was therefore on safe ground when he said that he knew that Pharaoh and his advisers were not yet G'd-fearing people.

2ידעתי כי טרם חיראון, "I know you do not yet fear, etc." Moses meant that Pharaoh's fear of G'd lasted only as long as the latest plague had not yet been removed. As soon as they would experience relief they would continue in their rebellious ways against G'd as previously. Moses referred to previous examples of Pharaoh reneging on his promise to let the Israelites go as proof for his present lack of faith in Pharaohs protestations.

3Moses made it plain that he did not consider that Pharaoh was deliberately being deceitful in trying to convince Moses that he should pray on his behalf; he was simply under psychological pressure at that time. This induced temporary fear of G'd in him and in his people. Moses wanted Pharaoh to know that he himself could read Pharaoh's mind, as Pharaoh would be the first to acknowledge. He added that even if Pharaoh were to try and prove that Moses was wrong in his prediction that he, Pharaoh, would renege after the hail had stopped, he would not be able to control his spirit sufficiently to keep his undertaking.