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.
ibnmajah:920Muḥammad b. al-Ḥārith al-Miṣrī > Yaḥyá b. Rāshid > Yazīd a freed slave of Salamah > Salamah b. al-Akwaʿ

“I saw the Messenger of Allah ﷺ performing the prayer, and he said one Salam.”  

ابن ماجة:٩٢٠حَدَّثَنَا مُحَمَّدُ بْنُ الْحَارِثِ الْمِصْرِيُّ حَدَّثَنَا يَحْيَى بْنُ رَاشِدٍ عَنْ يَزِيدَ مَوْلَى سَلَمَةَ عَنْ سَلَمَةَ بْنِ الأَكْوَعِ قَالَ

رَأَيْتُ رَسُولَ اللَّهِ ﷺ صَلَّى فَسَلَّمَ مَرَّةً وَاحِدَةً  


See similar narrations below:

Collected by Aḥmad
ahmad:9758Wakīʿ > Sufyān > ʿĀṣim b. Kulayb al-Jarmī > Abīhiʿan Abū Hurayrah

[Machine] I have only seen the Prophet ﷺ perform the Duha prayer once.  

أحمد:٩٧٥٨حَدَّثَنَا وَكِيعٌ قَالَ حَدَّثَنَا سُفْيَانُ عَنْ عَاصِمِ بْنِ كُلَيْبٍ الْجَرْمِيِّ عَنْ أَبِيهِعَنْ أَبِي هُرَيْرَةَ قَالَ

مَا رَأَيْتُ النَّبِيَّ ﷺ صَلَّى الضُّحَى قَطُّ إِلَّا مَرَّةً وَاحِدَةً