In Shahadah and Its Essential Conditions
, Yahya Ondigo details the seven necessary conditions for a Muslim's testimony of faith to be accepted by Allah. These include: knowledge, certainty, truth, compliance, acceptance, sincerity, and loving and hating for the sake of Allah. The shahadah is second nature to most Muslims, yet it is disappointing to note that many of them are not aware of the seven conditions attached to it.
This is a must-read text for all Muslims who wish to remain true to their testimony and ensure that they lead lives as true believers.