That the Messenger of Allah (ﷺ) used to say the taslim to his right and to his left.
The Book of Forgetfulness (In Prayer)
Sunan an-Nasa'i - Hadith 1316
Hadith Text
That the Messenger of Allah (ﷺ) used to say the taslim to his right and to his left.
Commentary on the Manner of Taslim
The taslim, being the concluding act of the prayer, must be performed with due reverence. The Prophet (ﷺ) would turn his face to the right side, saying "As-salamu 'alaykum wa rahmatullah" and then to the left, repeating the same. This comprehensive greeting encompasses the angels recording good deeds on the right and left, and the Muslims in prayer rows on both sides.
Scholarly Interpretation
Imam an-Nawawi states that the minimum fulfillment of taslim is one salam to either side, though the complete sunnah is to perform it to both sides. The wisdom behind this dual taslim lies in its completeness - it serves as a farewell to the prayer and a greeting to the angels and worshippers. The face should be turned sufficiently such that the whiteness of the right cheek becomes visible to someone behind when turning right, and similarly for the left side.
Legal Ruling (Hukm)
The majority of scholars hold that the taslim is a pillar (rukn) of prayer without which the prayer remains incomplete. Some Hanafi scholars consider it wajib (obligatory) rather than fard (essential pillar). The proof for its obligation lies in the consistent practice of the Prophet (ﷺ) and his command to "conclude your prayer with taslim."
Spiritual Dimensions
The taslim symbolizes the Muslim's emergence from the divine audience back into the worldly realm, carrying with them the peace and blessings attained in prayer. By greeting both sides, the worshipper acknowledges the spiritual presence surrounding them and prepares to extend the peace of prayer into all interactions thereafter.