Sahih al-Bukhari 6263
Sahih al-Bukhari · Book 79: Asking Permission · Shaking hands
Narrated Qatada:
حَدَّثَنَا عَمْرُو بْنُ عَاصِمٍ ، حَدَّثَنَا هَمَّامٌ ، عَنْ قَتَادَةَ ، قَالَ قُلْتُ لأَنَسٍ أَكَانَتِ الْمُصَافَحَةُ فِي أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم قَالَ نَعَمْ.
I asked Anas, "Was it a custom of the companions of the Prophet (ﷺ) to shake hands with one another?" He said, "Yes."