[Machine] When we used to pray behind the Prophet ﷺ, we would say, by motioning with his index finger, "Assalamu alaikum, assalamu alaikum". Then the Prophet ﷺ said to us, "What is wrong with some people who throw their hands in prayer as if they were the tails of horses? Is it not sufficient for any of you, or for one of you, to place his hand on his thigh, then to greet his brother from his right and left (side)?"
كُنَّا إِذَا صَلَّيْنَا خَلْفَ النَّبِيِّ ﷺ قُلْنَا يَعْنِي الْإِشَارَةَ بِإِصْبَعِهِ السَّبَابَةِ السَّلَامُ عَلَيْكُمْ السَّلَامُ عَلَيْكُمْ فَقَالَ لَنَا يَعْنِي النَّبِيَّ ﷺ مَا بَالُ أَقْوَامٍ يَرْمُونَ بِأَيْدِيهِمْ فِي الصَّلَاةِ كَأَنَّهَا أَذْنَابُ الْخَيْلِ الشُّمْسِ أَلَا يَكْفِي أَحَدَكُمْ أَوْ أَحَدَهُمْ أَنْ يَضَعَ يَدَهُ عَلَى فَخِذِهِ ثُمَّ يُسَلِّمَ عَلَى أَخِيهِ مِنْ عَنْ يَمِينِهِ وَعَنْ شِمَالِهِ