Is pronouncing the two testimonies and holding the belief sufficient for entering Islam?

Q: Is pronouncing and believing in this pillar of the pillars of Islam sufficient, or is it necessary to do other things for a person's Islam to be complete and his faith to be complete?

Answer: This pillar is what brings a disbeliever into Islam, by testifying that there is no god but Allah and that Muhammad is the Messenger of Allah, with truthfulness, certainty, knowledge of their meaning, and acting upon them, if he did not do so during his state of disbelief. Then he is required to perform the prayer and the remaining pillars and the rest of the rulings. For this reason, when the Prophet (peace and blessings be upon him) sent Mu'adh to Yemen, he said to him: .
He did not command them to pray until after tawhid (the oneness of Allah) and belief in the Messenger (peace and blessings be upon him). So disbelievers are first required to accept tawhid and belief in the Messenger (peace and blessings be upon him). When a disbeliever acknowledges this and embraces Islam, he has the ruling of Muslims. Then he is required to perform the prayer and the other matters of the religion. If he refuses to do so, other rulings apply to him.
Whoever refuses to pray is given the choice to repent; if he repents, well and good, otherwise he is killed as a disbeliever, unless he does not deny its obligation, according to the stronger of the two opinions of the scholars. If he refuses to pay zakah (the obligatory alms), opposes it, and fights to defend it, he is fought in the same way, as the Companions fought those who withheld zakah with Abu Bakr (may Allah have mercy on him) and ruled that they had committed apostasy. If he does not fight to defend it, the imam compels him to hand it over and punishes him with a discretionary punishment that deters others like him. Likewise, the Muslim is required to fast Ramadan, perform Hajj (the major pilgrimage) if he is able, and fulfill all that Allah has made obligatory upon him. He is also required to leave off what Allah has forbidden, because his entry into Islam and his commitment to it necessitate that. Whoever neglects something Allah has made obligatory or engages in something Allah has forbidden is dealt with according to what he deserves by the Shari'ah (Islamic sacred law).
As for the disbeliever who pronounces the two testimonies during his state of disbelief, like most disbelievers today, he is required to repent from what necessitated his disbelief, and his mere pronunciation of the two testimonies is not sufficient, because he has been saying them during his state of disbelief but did not act upon them. If his disbelief was due to worshipping the dead, the jinn, idols, or other created things, or seeking aid from them, or the like, it is obligatory for him to repent from that and to make his worship pure for Allah alone, and by that he enters Islam. If his disbelief was due to leaving off the prayer, it is obligatory for him to repent from that and to perform it, and if he does that, he enters Islam.
Likewise, if his disbelief was due to considering zina (unlawful sexual intercourse) or khamr (intoxicants) permissible, it is obligatory for him to repent from that; if he repents from that, he enters Islam.
Likewise, the disbeliever is required to leave off the action or belief that necessitated his disbelief; if he does that, he enters Islam.
These are great issues that a student of knowledge must pay attention to, and he must be well-informed about them. The scholars have clarified them in the chapter on the ruling of the apostate, which is a great chapter that a student of knowledge must pay attention to and read frequently. And success is from Allah.