The ruling on one who leaves a pillar of Islam

In truth, the sister’s question regarding Islam in Iraq is something that circulates among people. They say, for example: Islam is a condition for the validity of prayer, and Islam is also a condition for the validity of Hajj. So a person may be a Muslim even if he does not perform the other pillars of Islam. You have answered this before, but we would like this matter to be clarified as well?
Answer: This is clear. He is a Muslim by the two testimonies. When he affirms the two testimonies, unites Allah (Mighty and Majestic), and believes in His Messenger Muhammad (peace and blessings be upon him), he enters Islam. Then one looks at his actions: if he prays, his Islam is complete; if he does not pray, he becomes an apostate. Likewise, if he denies the obligation of prayer afterwards, he becomes an apostate. Or if he denies fasting, saying, “Fasting Ramadan is not obligatory,” he becomes an apostate. Or if he says, “Zakah is not obligatory; the zakah of Islam is not obligatory,” he becomes an apostate. Or if he says, “Hajj with the ability to perform it is not obligatory,” he becomes an apostate. Or if he mocks the religion, or insults the Messenger (peace and blessings be upon him), he becomes an apostate. Do we understand? This should be clear. So when he enters Islam by the two testimonies, he is ruled to be a Muslim. Then one looks at the remaining matters: if he stands firm upon the truth, his Islam is complete. If he does something that nullifies Islam, such as insulting the religion, denying the Messenger (peace and blessings be upon him), denying what Allah has made obligatory like prayer or fasting, or denying what Allah has forbidden, such as saying, “Zina is lawful,” he apostatizes from Islam with this, even if he prays and fasts. Even if he says, “I bear witness that there is no god but Allah and that Muhammad is the Messenger of Allah,” if he says, “Zina is lawful,” while he knows the evidence and the argument has been established against him, he becomes a disbeliever in Allah with major shirk, we seek refuge in Allah. Or if he says, “Intoxicants are lawful,” and the evidence has been explained to him and made clear to him, then he persists and says, “Intoxicants are lawful,” he commits major disbelief, apostasy from Islam, we seek refuge in Allah. Or if he says, for example, that undutifulness to parents is lawful, he apostatizes from Islam, we seek refuge in Allah. Or if he says that false testimony is lawful, he apostatizes from Islam after the legal evidence has been made clear to him.
Likewise, if he says, “Prayer is not obligatory,” “Zakah is not obligatory,” “Fasting Ramadan is not obligatory,” or “Hajj with the ability to perform it is not obligatory,” all of these are nullifiers of Islam, and he becomes a disbeliever.
The disagreement arises only if he says, “Prayer is obligatory, but I will not pray.” This is the point of disagreement: does he become a disbeliever or not? He says, “Prayer is obligatory, but I am lax and do not pray.” The majority of jurists say: he does not become a disbeliever, but is a sinner. He is given the opportunity to repent; if he repents, well and good, otherwise he is killed as a criminal.
Others among the scholars, and this is what is transmitted from the Companions (may Allah be pleased with them), hold that he becomes a disbeliever with major shirk. He is given the opportunity to repent; if he repents, well and good, otherwise he is killed as a disbeliever. This is based on the saying of Allah (Glorified and Exalted is He): [At-Tawbah: 5]. This indicates that the one who does not establish prayer is not left alone, but is given the opportunity to repent; if he repents, well and good, otherwise he is killed. And He said: [At-Tawbah: 11]. This indicates that the one who does not establish prayer—does not pray—is not a brother in religion. Yes.