Sibling love, disgrace, and quarrels
ואיש אשר-יקח את-אחתו בת-אביו או בת-אמו וראה את-ערותה והיא תראה את ערותו חסד הוא ונכרתו לעיני בני עמם ערות אחתו גלה עונו ישא
A man who will take his sister, the daughter of his father or the daughter of his mother, and will see her nakedness, and she will see his nakedness, it is chesed, and they will be cut off from before the eyes of the nation. For he has uncovered his sister’s nakedness, and he shall carry his sin
The Torah, in its list of the forbidden relationships, gives the incestuous relationship with one’s sister a special descriptor. The union is referred to as chesed. Normally, this word refers to loving kindness. It seems highly out of place in this context. Rashi therefore says that in this context it’s the Aramaic word for disgrace. Such a union is a disgrace to both parties. However, why did the Torah use this unusual word, instead of the normal Hebrew word for disgrace? Rashi therefore brings the homiletic interpretation, that this verse is alluding to the answer to an age-old question.