"A fool rejects his father's discipline, but he who regards reproof is sensible"
a fool rejects his father's discipline
The first part of the verse could be viewed with an “even this he won't do.” They will not even pay attention when someone who deeply loves them and is committed to their success tries and corrects them. They see it as messing with the life they want to lead. How tragic that some people will not be corrected. They want to do what they want; they want to think that they are the captain of their own ship regardless of what it costs them.
but he who regards reproof is sensible
The word regards is the Hebrew word samar which is keep, guard, observe, give heed to. One of the consistent things about the life of fools is that they are unwilling to notice when they are being spanked by their own choices. There are all kinds of reproofs in life: there are ones that come from authority where they correct us; there are ones that come through our finances – usually lack of money or debt; there are ones that come through friends – sometimes moving away from us; there are reproofs from driving – as in accidents that are our fault; there are reproofs from our career – such as not getting the promotion; there are reproofs from marriage – often tension or fights with our spouse; there are reproofs from our children – such as their rebellion or a lack of anything to talk about with them.
Reproofs are ways that God is trying to get our attention. He is saying what you are currently doing is not working; change. This is not the right way to act, speak, think, or go so go a different way. But the fool blames everybody else except themselves. They are completely oblivious that they might be the source of many of their problems.