How authentic is the Hadith: "Whoever says in Rajab, 'I ask forgiveness of Allah; there is no god but He, alone without partner, and I repent to Him' one hundred times, and concludes it with charity, Allah will seal for him with mercy and forgiveness. And whoever says it four hundred times, Allah will write for him the reward of one hundred martyrs"?

The hadith "Whoever says in Rajab, 'I seek forgiveness from Allah; there is no god but He'" is a fabricated hadith with no basis in the books of Sunnah and narrations (athar). It has not been narrated by any of the people of knowledge (scholars), nor has it even been mentioned in books of fabricated and forged hadiths. Rather, it was found in some Shiite books without a chain of narration (isnad), such as the book "Iqbal al-A'mal" by Ibn Tawus.

Signs of its fabrication are evident from several aspects: 1. The hadith lacks an isnad (chain of narration). 2. Only Rafidi (Shiite) books mention it. 3. It pertains to the virtues of the month of Rajab, for which many fabricated hadiths exist. 4. The exaggeration in reward by assigning a tremendous recompense (the reward of one hundred martyrs) for a simple act.