The practice of hitting children teaches them to become hitters. Extensive research is now available which indicates there is a direct correlation between physical punishment and violent behavior in teenagers and adults. As adults they feel it is appropriate to mistreat children and feel less compassion toward others. This makes it more difficult to have meaningful relationships as adults.
Children learn best through parental modeling.
Violence gives the message that hitting is an appropriate way to express one's feelings and to solve problems. If a child sees violence the cycle continues into the next generation. Although rod is mentioned many times in the Bible it is only mentioned in the Book of Proverbs in connection to child rearing. Solomon's method did not work very well for his own son Prince Rehoboam. Jesus taught that children are close to God and urged love, not punishment.