Hadithcore
Sahih al-Bukhari, 838
sahih

Narrated `Itban bin Malik:

We prayed with the Prophet (ﷺ) and used to finish our prayer with the Taslim along with him.

حَدَّثَنَا حِبَّانُ بْنُ مُوسَى، قَالَ أَخْبَرَنَا عَبْدُ اللَّهِ، قَالَ أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ مَحْمُودِ بْنِ الرَّبِيعِ، عَنْ عِتْبَانَ، قَالَ صَلَّيْنَا مَعَ النَّبِيِّ صلى الله عليه وسلم فَسَلَّمْنَا حِينَ سَلَّمَ‏.‏

References2 variants
In-Book Reference
Book 10, Hadith 231
USC-MSA web (English) reference
Vol. 1, Book 12, Hadith 800 (deprecated numbering scheme)
Sharh · explanationclick to expand
The Sahabah (may Allah be pleased with them) were very keen to follow in the footsteps of the Prophet (blessings and peace of Allah be upon him) in all things, and to transmit that to those who came after them, especially with regard to prayer, which is the foundation of faith. In this hadith, ‘Itban ibn Malik (may Allah be pleased with him) narrates a report about when to say the taslim when praying behind an imam. He tells us that the taslim of the Sahabah (may Allah be pleased with them), when they were praying behind the Prophet (blessings and peace of Allah be upon him), came at the same time as the taslim of the Prophet (blessings and peace of Allah be upon him). In other words, they would begin to say their salaam after he began to say his salaam and before he finished saying it. And it was said that this is not what is meant; rather what is meant is that they said the taslim straight after he finished his, with no lag, and this was expressed by suggesting this it happened at the same time, because when things come immediately after one another, it is almost like they are happening at the same time..