Is it serious if the teacher tells the students not to come to school?

Do you mean that teachers will have serious consequences, or students will have serious consequences if they encounter this situation?

If you are a teacher, you have no right to say so. Students can't be discouraged by any teacher. According to the compulsory education law, schools have no right to expel students during the compulsory education stage. If you say this angrily, you should take it back so as not to cause trouble. If you receive a complaint, just make angry remarks and explain to the school leaders why you can't help being so angry. This means telling the student's consistent performance realistically and making some self-criticism on his working methods, and things will pass without any serious consequences.

Please don't mind if you are a student and the teacher says so. Just go to school as usual. The teacher will not kick you out, and there will be no serious consequences. But you should obey the discipline and study hard in the future. The teacher was so angry that she said such cruel things, but she was helpless. He hates that iron can't be turned into steel. Rome was not built in a day. Solve the contradiction with the teacher with your own actions. As long as you make progress, the teacher will be happy.