The Prophet (may Allah's peace and blessings be upon him) clarified that if someone commits a sin that requires imposing a legally prescribed punishment, such as adultery or theft, and he is punished for it in this world, that punishment erases the sin and absolves him from its penalty in the Hereafter. This is because Allah is too generous and merciful to impose two punishments for the same sin on his slave. Moreover, if Allah conceals someone's sin in this world, and he is not punished for this sin, and Allah forgives and pardons him, then Allah Almighty is too gracious and generous to retract and punish for a sin He has already forgiven and pardoned.