Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
suyuti:1376a –

The Prophet ﷺ said: If two Muslims meet, shake hands, praise Allah, and ask Him for forgiveness, they will be forgiven. (Using translation from Abū Dāʾūd 5211)   

السيوطي:١٣٧٦a –

"إذا الْتَقَى المسلمانِ (فتصافَحَا) . وَحَمِدَا الله واستْغَفْراهُ غَفَر الله لَهُما".  

[ط] الطيالسي [د] أبو داود وابن أبي الدنيا في كتاب الإخوان، [ع] أبو يعلى وسمويه، وابن السنى، [ق] البيهقى في السنن [ض] ضياء المقدسي في مختاره عن البراء

See similar narrations below:

Collected by Abū Dāwūd, Suyūṭī
abudawud:5211 – ʿAmr b. ʿAwn > Hushaym > Abū Balj > Zayd Abū al-Ḥakam al-ʿAnazī > al-Barāʾ b. ʿĀzib

The Prophet ﷺ said: If two Muslims meet, shake hands, praise Allah, and ask Him for forgiveness, they will be forgiven.  

أبو داود:٥٢١١ – حَدَّثَنَا عَمْرُو بْنُ عَوْنٍ أَخْبَرَنَا هُشَيْمٌ عَنْ أَبِي بَلْجٍ عَنْ زَيْدٍ أَبِي الْحَكَمِ الْعَنَزِيِّ عَنِ الْبَرَاءِ بْنِ عَازِبٍ قَالَ

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا الْتَقَى الْمُسْلِمَانِ فَتَصَافَحَا وَحَمِدَا اللَّهَ ﷻ وَاسْتَغْفَرَاهُ غُفِرَ لَهُمَا