Q 30: What are the conditions of testifying that Muhammad is the Messenger of Allah? Could the first testimony (relating to Allah) be acceptable without this one?
A--- We have mentioned earlier that one cannot be deemed a Muslim until he declares these two testimonies, and that they are inseparable.
Thus, the conditions set for the first are deemed necessary for the second and vice versa.
Reference: 200 FAQ On Muslims Belief - Shiekh Hafiz Ibn Ahmed Al Hakami