“….If you buy a Hebrew slave he shall work for six years; in the seventh he shall go out to freedom without charge…” – Shemot 21:2

כִּי תִקְנֶה עֶבֶד עִבְרִי שֵׁשׁ שָׁנִים יַעֲבֹד וּבַשְּׁבִעִת יֵצֵא לַחָפְשִׁי חִנָּם – שמות כא, ב

The portion of Mishpatim, which immediately follows the Torah’s account of the awesome revelation at Sinai, opens with the law of a thief who was sold into slavery because he could not repay what he stole (see Rashi.)

With this law, the Torah sets the tone for the reality the Jews faced after Sinai. The bedrock of Torah observance is kabbolas ol, submitting to G-d’s kingship and authority. After we choose to be His subjects, we can proceed to serve Him by dutifully obeying His commands.  At Sinai, however, the Jewish people were shown “that G-d, He is the Lord: there is none else beside Him” (Devarim 4:35). Devotion to G-d was only natural under the influence of that awesome revelation, so a foundation of free-willed acceptance of G-d’s kingship could not be cemented in that environment.  True kabbolas ol became possible only afterward, when G-d’s presence was no longer obvious.

But with the freedom to submit to G-d’s authority came the freedom to ignore or reject it. Therefore, the portion immediately following the Giving of the Torah begins by forewarning the bitter end of a thief, because the most observable negative possibility of the post-Sinai freedom is thievery.

The Talmud (Bava Kama 79b) explains that a thief who steals covertly is worse, in a sense, than a robber who steals in the open. The robber he has no shame before man or G-d. The thief, on the other hand, recognizes the evil in what he is doing and fears being identified by man, yet he disregards the fact that he is being observed by G-d, Whose law he is willfully transgressing. The thief thus epitomizes the freedom to submit to or reject the kingship of G-d. We were therefore immediately warned about the extreme punishment of a thief, in order to prevent this pitfall of the post-Sinai reality and to steer us instead in the opposite direction.

—Toras Menachem, vol. 39, pp. 109-112