The Talmud (Yevamot 47a) teaches us that when a non-Jew comes to a rabbi seeking conversion to Judaism, the rabbi is supposed to try to dissuade him/her, and then if the candidate persists, teach him/her some mitzvot (commandments), and specifically the following (from this week's parashah, Qedoshim):
וּבְקֻצְרְכֶם אֶת-קְצִיר אַרְצְכֶם, לֹא תְכַלֶּה פְּאַת שָׂדְךָ לִקְצֹר; וְלֶקֶט קְצִירְךָ, לֹא תְלַקֵּט. וְכַרְמְךָ לֹא תְעוֹלֵל, וּפֶרֶט כַּרְמְךָ לֹא תְלַקֵּט: לֶעָנִי וְלַגֵּר תַּעֲזֹב אֹתָם, אֲנִי יְהוָה אֱלֹהֵיכֶם
Uvqutzrekhem et qetzir artzekhem, lo tekhaleh pe-at sadekha liktzor; veleqet qetzirekha lo telaqqet. Vekharmekha lo te-olel, uferet karmekha lo telaqqet. Le-ani velager ta-azov otam, ani Adonai Eloheikhem.
When you reap the harvest of your land, you shall not reap all the way to the edges of your field, or gather the gleanings of your harvest. You shall not pick your vineyard bare, or gather the fallen fruit of your vineyard; you shall leave them for the poor and the stranger: I the Lord and your God. (Leviticus 19:9-10)
Why did the rabbis of the Talmud identify these particular mitzvot, of all the possible choices in the Torah (roughly 613, depending on how you count), as the essential things that one who is joining the Jewish tribe needs to know? It points to the centrality of two features of Jewish life:
1. Gemilut hasadim - the obligation to take care of those in need with practical deeds of lovingkindness, i.e. supplying them with their basic needs;
2. Derekh eretz - literally, "the way of the land" - fundamental respect for others with whom we share our physical and spiritual environment.
Even though most of us today do not have fields that would allow us to fulfill these apparently agricultural mitzvot, we should go about our lives committed to the spirit of the text. The fundamental mitzvot are social rather than agricultural: take care of others, and play nice in the sandbox.