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.
bayhaqi:3406Abū ʿAlī al-Rūdhbārī > Abū Bakr b. Dāsah > Abū Dāwud > Ḥusayn b. ʿĪsá al-Khurāsānī al-Dāmighānī > Jaʿfar b. ʿAwn > Hishām b. Saʿd > Nāfiʿ > ʿAbdullāh b. ʿUmar

The Messenger of Allah ﷺ went to Quba to offer prayer. Then the Ansar (the Helpers) came to him and gave him a salutation while he was engaged in prayer. I asked Bilal: How did you find the Messenger of Allah ﷺ responding to them when they gave him a salutation while he was engaged in prayer. He replied: In this way, and Ja'far ibn Awn demonstrated by spreading his palm, and keeping its inner side below and its back side above. (Using translation from Abū Dāʾūd 927)   

البيهقي:٣٤٠٦أَخْبَرَنَا أَبُو عَلِيٍّ الرُّوذْبَارِيُّ أنبأ أَبُو بَكْرِ بْنُ دَاسَةَ ثنا أَبُو دَاوُدَ ثنا حُسَيْنُ بْنُ عِيسَى الْخُرَاسَانِيُّ الدَّامِغَانِيُّ ثنا جَعْفَرُ بْنُ عَوْنٍ ثنا هِشَامُ بْنُ سَعْدٍ ثنا نَافِعٌ قَالَ

سَمِعْتُ عَبْدَ اللهِ بْنَ عُمَرَ ؓ يَقُولُ خَرَجَ رَسُولُ اللهِ ﷺ إِلَى قُبَاءَ يُصَلِّي فِيهِ قَالَ فَجَاءَتْهُ الْأَنْصَارُ فَسَلَّمُوا عَلَيْهِ وَهُوَ يُصَلِّي قَالَ فَقُلْتُ لِبِلَالٍ كَيْفَ رَأَيْتَ رَسُولَ اللهِ ﷺ يَرُدُّ عَلَيْهِمْ حِينَ كَانُوا يُسَلِّمُونَ عَلَيْهِ وَهُوَ يُصَلِّي؟ قَالَ يَقُولُ هَكَذَا وَبَسَطَ كَفَّهُ وَبَسَطَ جَعْفَرُ بْنُ عَوْنٍ كَفَّهُ وَجَعَلَ بَطْنَهُ أَسْفَلَ وَظَهْرَهُ إِلَى فَوْقَ  


See similar narrations below:

Collected by Abū Dāwūd
abudawud:927al-Ḥusayn b. ʿĪsá al-Khurāsānī al-Dāmaghānī > Jaʿfar b. ʿAwn > Hishām b. Saʿd > Nāfiʿ > ʿAbdullāh b. ʿUmar

The Messenger of Allah ﷺ went to Quba to offer prayer. Then the Ansar (the Helpers) came to him and gave him a salutation while he was engaged in prayer. I asked Bilal: How did you find the Messenger of Allah ﷺ responding to them when they gave him a salutation while he was engaged in prayer. He replied: In this way, and Ja'far ibn Awn demonstrated by spreading his palm, and keeping its inner side below and its back side above.  

أبو داود:٩٢٧حَدَّثَنَا الْحُسَيْنُ بْنُ عِيسَى الْخُرَاسَانِيُّ الدَّامَغَانِيُّ حَدَّثَنَا جَعْفَرُ بْنُ عَوْنٍ حَدَّثَنَا هِشَامُ بْنُ سَعْدٍ حَدَّثَنَا نَافِعٌ قَالَ

سَمِعْتُ عَبْدَ اللَّهِ بْنَ عُمَرَ يَقُولُ خَرَجَ رَسُولُ اللَّهِ ﷺ إِلَى قُبَاءَ يُصَلِّي فِيهِ قَالَ فَجَاءَتْهُ الأَنْصَارُ فَسَلَّمُوا عَلَيْهِ وَهُوَ يُصَلِّي قَالَ فَقُلْتُ لِبِلاَلٍ كَيْفَ رَأَيْتَ رَسُولَ اللَّهِ ﷺ يَرُدُّ عَلَيْهِمْ حِينَ كَانُوا يُسَلِّمُونَ عَلَيْهِ وَهُوَ يُصَلِّي قَالَ يَقُولُ هَكَذَا وَبَسَطَ كَفَّهُ وَبَسَطَ جَعْفَرُ بْنُ عَوْنٍ كَفَّهُ وَجَعَلَ بَطْنَهُ أَسْفَلَ وَجَعَلَ ظَهْرَهُ إِلَى فَوْقٍ