What is intended by "altogether" (kāffah)?

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

1. The first opinion is that "kāffah" refers to "silm", meaning "enter into all the laws of Islam." This interpretation corresponds to the view that the verse was revealed about those from the People of the Book who had embraced Islam but continued to observe certain Jewish practices.
2. The second opinion is that "kāffah" refers to those entering Islam, meaning "enter all of you into Islam." This interpretation corresponds to the view that the verse was revealed about the People of the Book who had not yet believed in the Prophet Muḥammad (ﷺ).
3. Based on the third view, that the verse was revealed concerning the Muslims, "kāffah" could imply one of the following three meanings:

i. It could be a command for those who believe with their tongues to also believe with their hearts. ii. It could be a command for believers to enter into all the laws of Islam. iii. It could be a command to remain steadfast in Islam, like the verse "O you who have believed, believe" (4:136).