What is the meaning of "They could not enter them except in fear"?

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

1. It is an account of their condition thereafter. According to al-Suddī, no Roman enters the Temple of Jerusalem except in fear of being killed or having to pay the jizya (poll tax).
2. It implies a command although it is expressed as an informative statement. The implication is that you should strive in fighting against them so that none of them enters it except in fear.