I personally know the pain of the "discipline rod" My parents spanked me when I was a little child. Worse, I was sent to this horrible private Christian school, a fundamentalist school, they spanked my sister for no reason, and they threatened to spank me and scared me, demanded too much out of me. They made me hate school, I never liked school and had trouble with homework and schoolwork all because of them. They piled on homework starting in kindergarten. The teacher wanted to send me to the principle's office for a spanking because I had a hard time reciting my phone number and address.
In kindergarten 4 the teacher had all the kids sitting at their desks, the boy was passing out pencils, papers, teacher told us not to talk, the little boy told me not to touch my pencil, teacher said who talked, the little girl next to me pointed to me, teacher yelled or grabbed my face, said keep your little mouth shut. Other teachers I had problems with.
In public school I was sent to the school psychiatrist. My parents sometimes spanked me unfairly, and in public school spanking is not allowed. I think spanking is illegal all across the USA. It's called child abuse.
Have you heard of parents who beat their children to death? Now how does that help 'correct' them? I have heard of situations where babies and toddlers have been killed, murdered, by people trying to "discipline" them. Young children are very delicate and can easily be injured.