In Islam, major sins, known as kabair, are serious offenses that can lead to severe consequences in this life and the hereafter. These sins include actions such as shirk (associating partners with Allah), murder, theft, and adultery. Committing these acts is believed to distance a person from Allah and can result in punishment if not repented for. Repentance, or tawbah, is essential for Muslims who commit major sins. It involves feeling genuine remorse, seeking forgiveness from Allah, and making a firm intention not to repeat the sin. Islam emphasizes that Allah is merciful and forgiving, encouraging believers to return to the right path.