What is meant by the "sakīnah" in this āyah?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. It is a gentle breeze that has a face like that of a human being. [Abū al-Aḥwaṣ from ʿAlī]
2. It is a small and terrifying creature; during battles, it would extend its leg and shine its eyes at the enemy, causing them to flee. [Al-Ḍaḥḥāk from Ibn ʿAbbās]
3. It is a golden basin from Paradise in which the hearts of the prophets are washed. [Abū Mālik from Ibn ʿAbbās]
4. It is a spirit from Allah that speaks. Whenever they disagreed about something, it would speak to them and clarify what they wanted. [ʿAbd al-Ṣamad ibn Maʿqil from Wahb ibn Munabbih]
5. It refers to signs that they recognize and which bring them peace. [Ibn Jurayj from ʿAṭāʾ ibn Abī Rabāḥ, al-Zajjāj]
6. It means "dignity". [Maʿmar from Qatādah]
7. It refers to "mercy." [Al-Rabīʿ ibn Anas]