Is someone who cheats or lies frequently considered an infidel, even if they believe in Allah and the Last Day, based on the saying of the Messenger of Allah, peace and blessings be upon him: "Whoever cheats us is not of us"?

The Hadith: "Whoever cheats us is not of us" was narrated by Muslim, and it means to condemn the cheater and to clarify that he is not in line with the Muslim way of truthfulness and sincere advice. The Hadith does not mean that the cheater is an infidel. Sheikh al-Islam Ibn Taymiyyah explains that this deficiency in faith is a deficiency in the obligatory perfection, not a deficiency that invalidates the essence of faith. So, the cheater is not an infidel as the Khawarij claim, nor is he a complete believer who does not deserve punishment as the Murji'ah claim. Rather, he is a believer deficient in the obligatory faith, deserving reward for the faith he possesses, and punishment for the cheating. Al-Khattabi said that the meaning of "is not of us" is "is not upon our path and our methodology."