Jabir b. Samura reported: We said our prayer with the Messenger of Allah (ﷺ) and, while pronouncing salutations, we made gestures with our hands (indicating)" Peace be upon you, peace be upon you." The Messenger of Allah (ﷺ) looked towards us and said: Why is it that you make gestures with your hands like the tails of headstrong horses? When any one of you pro- nounces salutation (in prayer) he should only turn his face towards his companion and should not make a gesture with his hand.
Source: sunnah.com
Other translations
Arabic
وَحَدَّثَنَا الْقَاسِمُ بْنُ زَكَرِيَّاءَ، حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُوسَى، عَنْ إِسْرَائِيلَ، عَنْ فُرَاتٍ، - يَعْنِي الْقَزَّازَ - عَنْ عُبَيْدِ اللَّهِ، عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ صَلَّيْتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَكُنَّا إِذَا سَلَّمْنَا قُلْنَا بِأَيْدِينَا السَّلاَمُ عَلَيْكُمْ السَّلاَمُ عَلَيْكُمْ فَنَظَرَ إِلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ " مَا شَأْنُكُمْ تُشِيرُونَ بِأَيْدِيكُمْ كَأَنَّهَا أَذْنَابُ خَيْلٍ شُمُسٍ إِذَا سَلَّمَ أَحَدُكُمْ فَلْيَلْتَفِتْ إِلَى صَاحِبِهِ وَلاَ يُومِئْ بِيَدِهِ " .
sunnah.com