Amr bin Shu’aib reported on his father’s authority that his grandfather (May Allah be pleased with him) said:
Messenger of Allah (ﷺ) said, “Command your children to perform Salat (prayer) when they are seven years old, and beat them for (not offering) it when they are ten, and do not let (boys and girls) sleep together”.
Shaykh Ibn Baaz was asked:
What is the ruling of hitting the children whom are under the age of ten, and what should it be done over? What is your advice in regards to that?
The father and the mother are allowed to discipline the children if they see it fitting to do that, even if they are under the age of ten, and even if they maybe under seven. If they see that they should discipline their child, whether it be a boy or girl, there is no problem with that. But it should be with something which is appropriate for them and doesn’t harm them,. Light discipline which benefits them and doesn’t harm them.
If he is transgressing against his younger brothers, if he is playing in the house in a way which causes harm or similar to that, then he is disciplined with light beatings or with severe speech which will deter him, or preventing him from some of his needs which he desires until his manners become better.
(This should be the case) whether that be done by the mother, father, or his older brother. If he doesn’t have a father or mother, or by his paternal uncle or maternal aunt, (then) in accordance to his situation. Meaning, it is done by the one who nurtures him and takes care of him, (therein) he is allowed to discipline him.
Whether that be the mother, father, maternal uncle, maternal aunt, or older brother in accordance to the situation. Thus the one who nurtures him and takes care of him is allowed to discipline him with something which won’t harm him, something light but which benefit will occur from.
Shaykh Al Uthaymeen also mentions a benefit:
Yes, if the child will become disciplined by being hit and there is no other way, then there is no problem with that. The customs of the people have continued upon this. If the one whom is being disciplined is like a baby in the cradle (wherein) he starts to scream and thus his mother hits him, then this isn’t permissible because in it is causing pain without any benefit. It all depends on whether the child will be disciplined with this beating or not. If he will be, then he shouldn’t beat him and leave a mark, he shouldn’t beat upon the face, nor a lethal place.
Rather, he should only hit upon the back, shoulder, or that which is similar to it and shouldn’t be a means for his destruction. Beating on the face is a mistake because the face is the highest part of the human and the most honourable part of the human.
If he is hit on the face, he is afflicted with belittlement and embarrassment more then he would have felt if he was hit on his back. For that reason, it has been prohibited to hit the face.
The narration that prohibits hitting the face is:
Narrated Abu Huraira:
The Prophet (ﷺ) said, “If somebody fights (or beats somebody) then he should avoid the face.”
Reported by Bukhari and Muslim
Majid Jawed Al Afghanee