An important task for any writer is sentence unification within each paragraph and paragraph unification within each chapter. Rashi used three main methods of unification:
• unification by contrast
• unification by cause-effect-consequence
• unification by commonality.
The unification principle is not cosmetic. It is powerful leading to novelty in meaning and interpretation. Today's example shows this.

Verse Lv25-47:55 discussing the right of a Jewish poor person who sold himself to a non-Jew to redeem himself states And if a sojourner or stranger becomes rich by you, and your brother who dwells by him becomes poor, and sell himself to the stranger...
• After he is sold he may be redeemed again; ...
• And as a yearly hired servant shall he be with him; and the other shall not rule with rigor over him in your sight.
• And if he is not redeemed in these years, then he shall go out in the year of jubilee, both he, and his children with him.
• For to me the people of Israel are servants; they are my servants, whom I brought forth out of the land of Egypt; I am the Lord your God.

We see how all but the last bullet point to the right to leave slavery: We are told that he may a) redeem himself, b) leave at Jubilee; c) and while working should not be abused. In other words all but the last bullet point to a unified paragraph theme. Rashi explains the last underlined bullet as also contributing to this unified paragraph theme: The foundation of the Jewish people is the redemption from Egyptian slavery. A non-Jew who does not let a Jewish slave redeem himself contradicts the foundation of the Jewish people. In other words redemption from slavery is not just a nicety of Jewish law; rather it is the very foundation of the Jewish people.