The answer is: Death

Exo 21:15

In the context of Exodus 21, we encounter a society deeply invested in honor and respect, particularly towards parents. Here, the gravity of parental authority is illustrated starkly—hitting one's father isn't just a physical act; it symbolizes a severe breakdown in social and familial respect and cohesion. Given the significance of parental relationships in ancient Israelite culture, such a violent act warranted intense consequences—a death sentence.

Now, strikingly similar statutes are found in other ancient civilizations—notably the Code of Hammurabi, which, however, rates punishments differently based on social status and situations. This comparative angle gives us a glimpse of ancient values surrounding authority and respect, reaffirmed across varied cultures.

Interestingly, the command does not just swiftly mete out punishment; it layers in community values that enhance family bonds and societal order. Beyond mere law, it reflects the transformational power of familial relationships. Reverence towards one’s parents in Hebrew culture was partly based on the understanding that parents have significant experiences and wisdom to endow upon their children. This practice roots deep into parts of the wisdom literature, such as Proverbs, where honoring one's parents leads to long life (Proverbs 3:1-2).

Many modern interpretations highlight this command not only as preservation of social order but also challenge us to nurture not just obedience, but profound respect and love within families today—elements that also harmoniously resonate throughout many global communities.