To the reader unaware of the divisions of the Torah, the end of Parshat Behar seems odd. Instead of ending at the sensible conclusion of chapter 25, the portion ends after the first two verses of chapter 26. What the untrained reader does not know is that chapters and verses were applied to the biblical text by Christians in the Middle Ages while the division into Torah reading portions by the rabbis is far older. (Chapters were determined by the Archbishop of Canterbury in the thirteenth century. Verses were inserted by a French publisher in the sixteenth century.) Therefore, the real question is not why does the portion end with two verses from the ensuing chapter but why did chapter 25 not end after two more verses?
It seems that Christians concluded that the content of the two verses in question dealing with idolatry and Sabbath observance has nothing to do with the prior theme of the Jubilee year. Hence, they must be part of a new idea and, appropriately, consigned to a new chapter. However, the rabbis did not see these two verses as a new idea but the culminating idea of Jubilee theme.
The pre-eminent commentator RaShI (Leviticus 26:1) paraphrases the Talmud (Kiddushin20a) when he writes that since the Jubilee sets free an Israelite who, because of financial reversals, comes under the lordship of a non-Jew, the Israelite might see fit to emulate his master: “Since my master worships idols, so shall I. Since my master desecrates the Sabbath, so shall I.” Thus, the Torah comes to warn against this sort of behavior. Israelites must be loyal to God no matter their social circumstances. The prohibition against idolatry and the requirement to observe the Sabbath are absolute and inviolate.
Aside from explaining the division of the text, the Sages (and RaShI) implicitly recognize a human tendency, that is, the desire to fit in. Even those at the bottom of the social order – like slaves – want to feel that they are part of group. They do not want to seem like outcasts. It is bad enough to be in economic distress without also being thought of as outsiders. Here the Torah takes a stand. Despite the psychological need to fit in, there is the competing requirement to stand out.