"Doing the Right and Good": a Jewish meta-ethic

Rab Judah said in Rab's name: If one takes possession [of an estate lying] between [the fields belonging to] brothers or partners, he is an impudent man, yet cannot be removed. R. Nahman said: He can even be removed too; but if it is only on account of the right of pre-emption, he cannot be evicted. The Nehardeans said: He is removed even on the score of the right of pre-emption, for it is written, And thou shalt do that which is right and good in the sight of the Lord.

(18) הישר והטוב [AND THOU SHALT DO] THAT WHICH IS RIGHT AND GOOD [IN THE EYES OF THE LORD] — This refers to a compromise, acting beyond the strict demands of the law.

"You shall do what is right and good in God's eyes"-- Our Rabbis have a beautiful midrash on this verse. They have said: "this refers to compromising and going beyond the requirement of the letter of the law."

The intent of this is as follows: At first he [Moshe] stated that you are to keep his statues and his testimonies which he commanded you, and now that he is stating that even where he has not commanded you, give thought as well, to do what is good and right in his eyes, for he loves the good and the right.

Now this is a great principle, for it is impossible to mention in the Torah all aspects of man's conduct with his neighbors and friends, and all his various transactions, and the ordinances or all societies and countries. But after He mentioned many of them- such as "Thou shalt not go about as a talebearer;" (Lev 19:16) "Do not seek revenge or bear a grudge;" (19:18) "Do not stand idly by the blood of your neighbor;" (19:16) "Do not curse the deaf;" (19:14) "You shall rise before an elder;" (19:32) and the like, He then went back and said generally that one should do the good and the right in everything, until through this he reaches [the level of] 'compromise and going beyond the letter of the law.'

This is like what it says of the law of the neighboring landowner (BM 108a), and even what they said (Yoma 86a): his beard should be nice and his speech should be gentle with people," until he is worthy of being called "pure and right" with regard to everything.