The Mekhilta DeRabbi Yishmael examines the Shabbat (the Sabbath) commandment's reference to "your man-servant and your maid-servant," asking a pointed question: which servants does the Torah mean?
The initial answer is that these are "children of the covenant," meaning servants who have been circumcised and accepted the commandments, Jewish servants or fully converted household members who are bound by the Torah's laws.
But the Mekhilta anticipates an objection. Perhaps "man-servant" refers to an uncircumcised servant, a non-Jewish bondsman who has not entered the covenant. The text rejects this possibility by pointing to another verse. (Exodus 23:12) states: "and there be refreshed the son of your maid-servant and the stranger." That verse already addresses the uncircumcised servant's right to rest on Shabbat. Since the Torah provides for uncircumcised servants elsewhere, the reference to "your man-servant and your maid-servant" in the Ten Commandments must refer to a different category.
The conclusion is that the Shabbat commandment's servants are children of the covenant, people who are themselves obligated in the commandments. The Torah is not being redundant. Each verse addresses a different legal category, and each servant receives Shabbat rest under a different provision.
This careful parsing ensures that no one is left out. Whether a servant is circumcised or uncircumcised, whether they are a child of the covenant or a resident stranger, the Torah guarantees them rest on the seventh day through one legal mechanism or another.