(1) Some time afterward, God put Abraham to the test. He said to him, “Abraham,” and he answered, “Here I am.”
Rav Aharon Lichtenstein, Does Judaism Recognize an Ethic Independent of Halakhah? Leaves of Faith, Vol. 2, pg. 34
As Benjamin Whichcote, the seventeenth-century Cambridge Platonist, pointed out, one cannot ask "Shall, then, the judge of the whole earth not to justice?" unless one assumes the existence of an unlegislated justice to which, as it were, God himself is bound...
למה נקוד על איו שבאליו לימדה תורה דרך ארץ שישאל אדם באכסניא שלו
Why are there dots in the Torah scroll upon the letters alef, yod, and vav in the word “to him [eilav]”? These letters spell ayo, which means: Where is he? The Torah is teaching the proper etiquette, which is that a person should inquire of his hostess about his host, just as he should inquire about the welfare of his hostess from the host.
(ה) רַבִּי נְחוּנְיָא בֶּן הַקָּנָה אוֹמֵר, כָּל הַמְקַבֵּל עָלָיו עֹל תּוֹרָה, מַעֲבִירִין מִמֶּנּוּ עֹל מַלְכוּת וְעֹל דֶּרֶךְ אֶרֶץ. וְכָל הַפּוֹרֵק מִמֶּנּוּ עֹל תּוֹרָה, נוֹתְנִין עָלָיו עֹל מַלְכוּת וְעֹל דֶּרֶךְ אֶרֶץ:
(5) Rabbi Nechunya ben Hakanah says: Anyone who accepts the yoke of Torah upon himself, they lift from him the yoke of government and the yoke of the way of the world (derekh erets). And anyone who casts from himself the yoke of Torah, they place upon him the yoke of government and the yoke of the way of the world (derekh erets).
תנו רבנן ארבעה צריכין חזוק ואלו הן תורה ומעשים טובים תפלה ודרך ארץ... דרך ארץ מנין שנאמר חזק ונתחזק בעד עמנו וגו׳:
Connected to the emphasis on the need to bolster one’s effort in prayer, the Gemara notes that the Sages taught in a baraita: Four things require bolstering, constant effort to improve, and they are: Torah, good deeds, prayer, and occupation... From where is it derived that occupation requires bolstering? As it is stated: “Be strong and we will be strong for the sake of our nation and for the cities of our God” (II Samuel 10:12).
The way of the earth - If he is an expert, for his work; if he is a merchant, for his merchandise; if he is a warrior, for his battle.
תנו רבנן אשר בנה אשר נטע אשר ארש לימדה תורה דרך ארץ שיבנה אדם בית ויטע כרם ואח"כ ישא אשה
§ The Sages taught (Tosefta 7:20-21): The Torah states: “What man is there that has built” (Deuteronomy 20:5), and then “that has planted” (Deuteronomy 20:6), and finally “that has betrothed” (Deuteronomy 20:7). The Torah has taught a person the desired mode of behavior: A person should build a house, then plant a vineyard, and afterward marry a woman.
R. Samson Raphael Hirsch, Religion Allied to Progress
Our aims also include the conscientious promotion of education and culture, and we have clearly expressed this in the motto of our Congregation: An excellent thing is the study of the Torah combined with the ways of the world [Yafeh talmud torah im derekh erez].
כָּל שֶׁיֶּשְׁנוֹ בַמִּקְרָא וּבַמִּשְׁנָה וּבְדֶרֶךְ אֶרֶץ, לֹא בִמְהֵרָה הוּא חוֹטֵא, שֶׁנֶּאֱמַר (קהלת ד) וְהַחוּט הַמְשֻׁלָּשׁ לֹא בִמְהֵרָה יִנָּתֵק. וְכָל שֶׁאֵינוֹ לֹא בַמִּקְרָא וְלֹא בַמִּשְׁנָה וְלֹא בְדֶרֶךְ אֶרֶץ, אֵינוֹ מִן הַיִּשּׁוּב:
Anyone who is [involved in] Scripture, the Oral Law, and proper social behavior will not easily [come to] sin, as it is stated, "And the three-ply cord is not quickly severed" (Ecclesiastes 4:12). Anyone who is not [involved in] Scripture, and not in the Oral Law, and not in proper social behavior is not part of civilization.
אינו מן הישוב. אינו מועיל לישובו של עולם. והוי מושבו מושב לצים, ופסול לעדות:
He is not from the settlement. He does not assist in the civilizing of the world. And his sitting is one of clowns, and he is disqualified from testimony.
Rav Lichtenstein, Leaves of Faith, Vol. 2, pg. 34
The wide-ranging concept of derekh eretz – roughly the equivalent of what Coventry Patmore called “the traditions of civility” – points in the same direction. Its importance again, not as descriptively synonymous with conventional conduct but as prescriptive lex naturalis should not be underestimated. The Mishnah cites Rabbi Eliezer b. Azariah’s view that “without Torah, there is no derekh eretz, and without derekh eretz, there is no Torah”; and the Midrash goes beyond this dialectical reciprocity, stating that “derekh eretz preceded Torah”… Their link reinforces our awareness of the rabbis’ recognition of natural morality.
Rav Kook, Orot ha-Torah 12:2-3
Every element of Torah must be preceded by derekh eretz. If it is something agreeable to natural reason and uprightness, it must pass in a straight path, with the inclination of the heart and consent of the pure will implanted in man, like theft, illicit sexual relations, and modesty which are learned from the ant, the dove, and the cat, and all the more so those things which are derived from the internal cognition of man himself and his spiritual sense…
דְּאָמַר רַבִּי יִשְׁמָעֵאל בַּר רַב נַחְמָן עֶשְׂרִים וְשִׁשָּׁה דוֹרוֹת קָדְמָה דֶּרֶךְ אֶרֶץ אֶת הַתּוֹרָה, הֲדָא הוּא דִכְתִיב (בראשית ג, כד): לִשְׁמֹר אֶת דֶּרֶךְ עֵץ הַחַיִּים, דֶּרֶךְ, זוֹ דֶּרֶךְ אֶרֶץ, וְאַחַר כָּךְ עֵץ הַחַיִּים, זוֹ תּוֹרָה.
Rabbi Ishmael son of Rav Nachman said: Derech eretz precedes Torah by 26 generations, since it is written “and to guard the way to the Tree of Life” (Genesis 3). “Way” is the derech eretz, and only after that comes “Tree of Life” which is Torah.
Tanchuma Yashan 10a
What is the way of the entire world? One who acquires slaves does so on condition that they bathe him, anoint him, clothe him, load him up, and provide light for him. However, God did not do this for the Israelites; rather, he did not lead them in the way of the land. He bathed them… and lit them way for them.
(31) And the older one said to the younger, Our father is old, and there is not a man on earth to consort with us in the way of all the world.
וירא את ענינו ואמרינן זו פרישות דרך ארץ
And let us derive it from affliction stated with regard to Egypt, as it is written: “And He saw our affliction” (Deuteronomy 26:7). We say that this verse is referring to abstinence from conjugal relations.
מדרש שמואל אבות ו:ד
(ח) וַתֹּאמֶר הַבְּכִירָה אֶל הַצְּעִירָה אָבִינוּ זָקֵן וגו' (בראשית יט, לא), שֶׁהָיוּ סְבוּרוֹת שֶׁנִּתְכַּלָּה הָעוֹלָם כְּדוֹר הַמַּבּוּל. (בראשית יט, לב): לְכָה נַשְׁקֶה אֶת אָבִינוּ יַיִן וגו', רַבִּי תַּנְחוּמָא מִשּׁוּם רַבִּי שְׁמוּאֵל (בראשית יט, לב): וּנְחַיֶּה מֵאָבִינוּ זָרַע, וּנְחַיֶּה מֵאָבִינוּ בֵּן אֵין כְּתִיב כָּאן אֶלָּא וּנְחַיֶּה מֵאָבִינוּ זָרַע, אוֹתוֹ זֶרַע שֶׁהוּא בָּא מִמָּקוֹם אַחֵר, וְאֵי זֶה זֶה מֶלֶךְ הַמָּשִׁיחַ.
The elder daughter said to the younger: Our father is elderly, etc. For they thought the world had been destroyed as the generation of the Flood.
Let us give our father to drink, etc. Rabbi Tanchuma son of Rabbi Shmuel says, "And we shall bring to life seed from our father" - it is not written "we shall bring to life from our father a son," but "we shall bring to life from our father a seed." [This refers to] the seed that comes from elsewhere, namely the Messianic King.