The Torah states: "And if these three he does not do to her, then she shall go out free, without money" (Exodus 21:11). The Mekhilta asks the obvious question: what are "these three"? Two possible answers emerge, and the correct one depends on understanding the context of the verse.
The first interpretation identifies the three options available to the master regarding the Hebrew maid-servant: marry her himself, marry her to his son, or facilitate her redemption. If he does none of these three things, she goes free without any payment. The master loses his investment because he failed to fulfill any of the purposes for which the sale was permitted in the first place.
The second interpretation suggests that "these three" refers to the three marital obligations: food, clothing, and conjugal time. If the master-turned-husband withholds all three, the wife goes free. Under this reading, the verse establishes grounds for the dissolution of a marriage based on material and physical neglect.
The Mekhilta rejects the second interpretation on contextual grounds. Would you say that? The verse speaks of a Hebrew maid-servant who has not yet been betrothed. Food, clothing, and conjugal time are obligations that arise within a marriage. But the maid-servant in question has not been married. She has not been designated as a wife by the master or betrothed to his son. The three marital obligations do not yet apply to her.
Therefore, "these three" must refer to the three courses of action: personal marriage, marriage to his son, or redemption. When all three options are exhausted or refused, the maid-servant walks away. She is free, and the master receives nothing for her departure.