Do Major Sins Make A Person Disbeliever
Understand the Law of Allah. What happens is that Allah may reveal the truth to a person. In case of Sahabah, the truth was made clear by the Messenger (PBUH). In face of truth, if a person makes some mistakes and amends them, then there is nothing to worry about. But in face of truth, if someone intentionally and knowingly rebels, then it is considered to be a serious sin. Allah then advises such a person. If such a person ignores His advice, He starts to send warnings of punishment. Then If such a person ignores even the warnings and continues to do reject truth and do sins. Then he is considered a kafir by Allah. Then Allah gives the kafir a time period to reconsider his course of actions and repent before the ultimate punishment. If the kafir refuses to repent even after that, then he is punished in this life (in case of Itmam-e-Hujjat in presence of a Messenger in this life). What Allah will ultimately do to kafir in the afterlife is yet to be seen. But we do not know who is a kafir and who is not so do not go labelling yourself or anyone as kafir. In case of the Hadiths you mentioned, the truth was made plain by the Messenger (PBUH), therefore there was less room for people to be making mistakes and they were likely to be kafir (because that is what Allah was making plain in that particular era). In modern time, a person may not understand or even be convinced of truth, therefore no one will get labelled off as a kafir as easily as you think. Do not worry and trust Allah, He is far more understanding and merciful than your OCD thoughts make Him out to be. https://www.youtube.com/watch?v=jznZ8TIK9qA
Indeed. Allah does not make your faith disappear over a single sin. The kafirs that are condemned in the Qur’an are the people who lived their entire life committing acts of kufr consistently and everytime Allah advised and warned them, they rebelled by committing more acts of kufr. Even then Allah kept the door of forgiveness open for a long period of time. If Allah can show such tolerance to kafir, then surely He is far more tolerant to Muslims. So as long as a Muslim repents, he can hope for forgiveness, he does not need to have perfect faith. And if he isn’t given chances to repent then Allah will compensate through His justice. The problem with kafir who will have a difficult time in Hereafter is usually that they do not care about their sins so they reject every advice, warning and chance to repent. If you are showing concern over kufr, then chances are, you are not on the path of kufr. Because this is a sign of taqwa and that is what the Hadiths are aiming at.