"We do not accuse anyone among the people of the qiblah of disbelief for any sin, so long as he does not deem it lawful, because of his (SAW) saying ‘Do not accuse the people of your qiblah of disbelief:" What is meant by ‘the people of the qiblah’ is those who both pray towards the Kaaba and are convinced of the entire Sacred Law conveyed by the Prophet gf. This is why the author previously said, ‘We declare those who face our qiblah to be Muslims [...] so long as they continue to acknowledge what the Prophet (SAW) conveyed’

A [believing] slave does not leave the faith [of Islam] except by rejecting what caused him to enter therein, because disbelief and faith are opposites: one is not nullified except by doing the other; and because a believer only became a believer and entered the faith [of Islam] through conviction and affirmation. Hence he does not become a disbeliever and leave the faith [of Islam] except by rejection and denial. Even if he were to commit an enormity, so long as he has sure belief, conviction and faith, he remains a believer. No one is adjudged a disbeliever until it is known from him that he patently denies what rendered him a believer [in the first place]."

Excerpt from: Imam al-Tahawi’s Creed of Islam: An Exposition

"Creeds articulate the principal points that define a person’s faith and explicate the fundamental convictions concerning Allah, His prophets, scriptures, angels and eschatological truths. These are essential in that they provide clarity about one's belief and guard one against theological heterodoxies and aberrations. They form the basis for a person's acts of worship, without which such actions are of no avail. The Prophet, in many of his sayings, issued a dire warning against aberrancy and innovation. He g& said, ‘Whoever then dissents will dissent into Hell? (narrated by al-Hakim) and ‘Allah will not accept prayer, fasting, charity, hajj, umrah, jihad and voluntary and obligatory actions (sarf wa ‘adl) from an innovator. He will be removed from Islam just as a hair is removed from dough: (Narrated by al-Bayhaqi.)

...The Creed of Imam Abi Ja‘far al-Tahawi (d. 321/933) is arguably the most acclaimed and universally accepted, It is, moreover, one of the earliest works on creed; and its enduring appeal among Sunni scholarly circles is attested by the numerous commentaries written on it, the various languages it has been translated into, and the many Islamic seminaries at which it is the primary creedal text that is taught."