Allah says in Surah al-A'raf:

“Say, “My Lord has forbidden immoralities—both open and secret—and sin, and unjustified aggression, and that you associate with Allah anything for which He revealed no sanction, and that you say about Allah what you do not know.””

What Allah has forbidden to His slaves are:

1. "Open and concealed fornication."

Fornication is a great evil. These things are prohibited by God, whether open or secret.

2. "Sin."

The own sins of sinners.

3. "Unjustified aggression".

That is, injustice, oppression, and hostility toward people.

4. "Polytheism, to associate with Allah that for which He had sent down no evidence."

Whatever type of polytheism is haram.

5. “You say about Allah what you do not know”

It is permissible to meditate on the essence of Allah and theology only on the basis of true knowledge. It is impossible to conjecture or imitate to someone.