The plagues were all unpleasant, yet they grow more severe. Initially the plagues and their effects are reversed. Later, people were killed (v14, 25), and only in the Passover were large numbers of Egyptians killed.
v1: The repeated request, that the people be released to worship the Lord, as in v13. This brings an important emphasis; the children of Israel were redeemed to worship God.
v2-3: A fresh threat, of a "terrible plague" upon the livestock in the field.
v4: Again, the livestock belonging to the children of Israel would be distinguished. Not one animal would die.
v6-7: The promise was fulfilled, as the livestock died. Pharaoh checked that the Israelite animals had been preserved.
The plague of boils fell upon other animals, not livestock, which had all died. By the time of the plague of hail, the Egyptians had obtained more livestock, to replace what was lost.
v8-9: The sixth plague, of boils.
v10: The soot was taken from a furnace; Egypt itself is elsewhere described as a furnace.
v11-12: The enemy could not stand before Moses, but Pharaoh still did not repent. The Lord hardened his heart. See also 10.1,20. The hardening by the Lord indicates a consistent rejection of the claims of God on his life, and a refusal to repent.
v13: The repeated request, from the Lord God of the Hebrews, speaking on behalf of His people.
v14: The plagues would become more severe; "the full force of my plagues". This implies that the Lord God had shown restraint in the previous plagues.
v15-16: God had shown His mercy in the plagues, for He could have destroyed the whole nation of Egypt by this stage. The plagues were to be a testimony to God's power; see Josh 2.10-11; 9.9-10. Compare also 2 Kings 2.24, where youths were mauled, and therefore scarred, rather than killed. The Lord goes further, by stating that Pharaoh had been raised up so that God's power be demonstrated; see Rom 9.17. It seems that, from Rom 9.18, God had mercy on Pharaoh AND He hardened his heart.
v17: Pharaoh remained stubborn and hard-hearted, refusing to heed the command of God, and maintaining his dominion over the people of God, and his opposition to the people of God.
v18-19: The worst hailstorm ever experienced, but again tempered with mercy. This was the seventh plague. God, in His mercy, gave a clear warning to the people of Egypt. To avoid the effects of the hail, the people should bring their livestock and servants under cover.
v20-21: Some heeded the warning, and others ignored it. Those who ignored the warning caused the suffering of their slaves.
It may have been, when the Lord God gave orders for the people to apply blood to their doorposts and lintels, and so avoid the destruction of the Passover, some Egyptians did this also; although 12.30 suggests that every household in Egypt suffered loss. But 12.38 speaks of a mixed multitude, leaving with the children of Israel; perhaps some Egyptians and other races allied themselves with the Israelites.
v22-25: The description of the dreadful hailstorm, with thunder and lighting.
v26: Again, the children of Israel were exempted from the plague.
v27-28: Apparent regret from Pharaoh. Note that he does not speak of personal wrong, but "my people are in the wrong". We do tend to avoid personal admission of guilt. Pharaoh asked again for the plague to be removed, and said that the children of Israel could leave.
v29: Moses was God's man. Time and again, at his word, the plagues stopped, as here.
v30: But Moses knew that Pharaoh and his leaders would not let the children of Israel go.
v31-32: The impact upon the crops. Such details are indicative of the accuracy of the account here.
v33: Again the plague stopped in answer to Moses' prayer.
v34-35: Pharaoh sinned again, by refusing the let the people go.