“strike.” The Hebrew verb is nakah (#05221 נָכָה), and it is a hiphil (causative) imperfect (uncompleted action), so “strike” here does not refer to a single blow. At the very least it refers to a beating, which may involve many blows or lashes. It may be more than one beating, as the behavior of the fool demands. This verse never says the mocker will change his thinking, and this verse is not about changing a mocker even though usually even a mocker will not repeat the thing that caused him to be beaten just so he avoids getting beaten again. However, when the mocker is beaten, the simple learn. And learn they must, or society goes into a downward spiral, with each generation being more foolish, godless and cruel than the last. Corporal punishment such as flogging may seem cruel to some, but the Word of God sets it forth as an important part of having a godly society.