Are congratulatory phrases such as "Ramadan Kareem," "Mubarak Alaikum Al-Shahr," "Sah Ramadanukum," and "Sah Futorkum" considered bid'ah (innovation in religion), or do they fall under the category of common and customary speech?

The Prophet, peace and blessings be upon him, used to give his companions the glad tidings of Ramadan's arrival, which some scholars consider a basis for people congratulating one another on its advent. It is reported in the Hadith that the Prophet, peace and blessings be upon him, used to say to his companions: "Ramadan has come to you, a blessed month. Allah has obligated its fasting upon you. In it, the gates of Paradise are opened, the gates of Hellfire are closed, and the devils are shackled. In it is a night better than a thousand months. Whoever is deprived of its goodness is indeed deprived." Al-Hafiz Ibn Rajab mentioned that this Hadith is a basis for people congratulating one another on Ramadan.

Imam Ahmad held that the matter of congratulating on religious occasions, such as saying "May Allah accept from us and from you" on Eid, is broad and permissible. Verbal and customary actions are originally permissible unless there is a text prohibiting them or they involve a religious harm, as affirmed by العلامة السعدي (Al-Allamah Al-Sa'di). Congratulations on occasions are customs intended for believers to supplicate for one another and to strengthen love and unity of hearts. It is obligatory to respond appropriately to whoever initiates the congratulations.