דם, צפרדע, and כנים demonstrated to the Egyptians that they themselves were merely גרים in their own land and hence were hardly in a position to treat Israel as גרים and deprive them of their rights.
ערוב, דבר, and שחין showed them how illusory were the notions that had made them feel superior to the people whom they had reduced to עבדות.
ברד, ארבה, and חשך were עינויים that made the Egyptians feel what it means to have to submit to a systematic regime of עינוי.
מכת בכורות concluded the series and finally brought about Israel's redemption.
Accordingly, the plagues can be arranged as follows:
- גרות: דם, צפרדע, כנים
- עבדות: ערוב, דבר, שחין
- עינוי: ברד, ארבה, חשך
- מכת בכורות
Each of these three groups of plagues was intended to cure the Egyptians of the delusion that they had the right to inflict גרות, עבדות, and עינוי upon the Israelites. דצ"ך was to accomplish this purpose by demonstrating God's power over water and land; עד"ש, by demonstrating God's power over the inhabitants who lived on the land; and באח"ב, by demonstrating God's power over the atmosphere that surrounded the land and its inhabitants.