1. Experience inheritance: Parents often pass on their knowledge and experience to their children by telling their past stories and experiences to help them better cope with the challenges in life.

2. Want children to change: Parents want their children to listen to their own words and change their behavior, so they adopt a didactic approach, hoping to influence their children by emphasizing key points and reasons.

3. Expression of love: Parents may think that preaching is a way to pay attention to and take care of their children and express their love and care for them.

4. Cultural tradition: In some cultures, it has become a habit and tradition for parents to educate their children by preaching, which is regarded as a necessary means of education.

However, excessive use of preaching may cause children's disgust and resistance, because children are more willing to learn and grow through their own experiences and practices. Therefore, parents should look for more active, supportive and interactive educational methods, such as encouraging children to think independently, gently guiding and educating children, and giving positive feedback and rewards.