What is meant by "establishing the prayer"?

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

1. It is to perform it properly in the prescribed manner. [Ibn ʿAbbās and Mujāhid]
2. It is to observe it on time, with ablution, bowing, and prostration. [Qatādah, Muqātil]
3. It is to perform it regularly. In the Arabic language, they say "qāʾim" for something that occurs regularly. [Ibn Kaysān]