What does "stand before God in qunūt" mean?

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

1. It refers to obedience. [Ibn ʿAbbās, al-Ḥasan, Mujāhid, Ibn Jubayr, al-Shaʿbī, Ṭāwūs, al-Ḍaḥḥāk, Qatādah, ʿAṭāʾ]
2. It refers to prolonging the standing in prayer. [Reported from Ibn ʿUmar, al-Rabīʿ ibn Anas, ʿAṭāʾ]
3. It refers to refraining from speaking during prayer. Zayd ibn Arqam states, "We used to speak during prayer until the verse 'And stand before Allah, qānitīn' was revealed, and we were commanded to be silent and prohibited from speaking."