Leviticus 20:9, Curses his father. The primary meaning of the Hebrew word for curse (qalal) is “to be light or slight.” The result of qalal is the lowering of another’s esteem or prestige causing disgrace or dishonor.
The same word is used in Proverbs 30:11–13 where it is considered filthiness to curse one’s parents and then, in pride, to maintain one’s innocence.
Qalal is used in Ezekiel 22:7 where this word is translated as “to make light of father and mother.” The prophet equates this sin with that of oppressing the stranger, mistreating the fatherless and widow, despising YHVH’s holy things, profaning his Sabbaths, slandering that leads to bloodshed, acts of lewdness, the committing of various sexual abominations, taking bribes, and practicing usury and extortion.
To curse one’s parents is to curse or to attack Elohim who gives one life through one’s parents. To disrespectfully treat one’s parents is to rebel against God-ordained authority — a sin which leads to a host of other acts of rebellion. As the saying goes, charity begins at home.
Likewise, criminality begins at home when a child refuses to respect his parents and the laws they have established in the home for the safety and benefit of all therein. Respect for one’s parents leads to stable and law-abiding citizenry; disrespect leads to lawlessness and criminality. This is why the Torah deems the sin of cursing one’s parents as a capital offense.