What is the punishment for swearing by Allah falsely, and how can one atone for this sin so that Allah may accept repentance and forgive, and is it permissible to swear falsely to save a certain situation?

False swearing is a characteristic of hypocrites and Jews. It deprives the one who commits it of a share in the afterlife. Allah warns against excessive swearing. Scholars have differed regarding the expiation for false swearing. The majority hold that there is no expiation, but rather repentance, while Imam Al-Shafi'i and a group of others mandated it. Combining repentance with expiation is safer. False swearing is permissible for a legitimate Islamic interest, such as gaining a benefit or averting harm, and it may even be obligatory in some cases. It is better to use equivocation (Tawriya). The proof for the permissibility of lying in these situations is what was narrated by Umm Kulthum, may Allah be pleased with her, in the Prophet's hadith, peace and blessings be upon him.