The ruling on adding (and His blessings) to the closing salam of the prayer

Question:
His second question says: When the one praying finishes his prayer and wants to say the salam, should he say: (Peace be upon you and Allah’s mercy and His blessings) to the right and then to the left, or should he say: (Peace be upon you and Allah’s mercy) only? And what is the ruling on the prayer of one who does that by adding (and His blessings)?

Answer:
What is preserved in the Sunnah is (and Allah’s mercy) only, and this is what is prescribed: to say (Peace be upon you and Allah’s mercy) to his right and his left. As for adding (and His blessings), there is disagreement among the scholars. Alqamah ibn Wa’il narrated from his father that the Prophet (peace and blessings be upon him) said it this way: But there is disagreement among the scholars regarding Alqamah’s narration from his father; some of them authenticated his hearing it from him, and some said that it is a broken chain.
Therefore, the believer should not add it, and the better and more preferable thing is to restrict himself to (and Allah’s mercy). If one adds it thinking it is correct or being ignorant of the matter, there is no blame on him; his prayer is valid. But the better and more cautious thing is not to add it, in order to avoid the disagreement of the scholars and to act according to the most established and strongest evidence. Yes.