
“D'`alakh s'nai l'khavrekh la ta`avaid. Zo hi kol hatora kulahh, ve'idakh perusha hu: zil g'mor”
That which is hateful to you, do not do to your neighbor. That is the whole Torah; the rest is the explanation. Go and study it.
Babylonian Talmud, tractate Shabbat 31a