'As long as you do not feel ashamed, do whatever you wish', the placing of one hand on the other in prayer (one places the right hand on the left), being quick to break the fast, and delaying the meal before dawn."  

أَنَّهُ قَالَ مِنْ كَلاَمِ النُّبُوَّةِ إِذَا لَمْ تَسْتَحِي فَافْعَلْ مَا شِئْتَ وَوَضْعُ الْيَدَيْنِ إِحْدَاهُمَا عَلَى الأُخْرَى فِي الصَّلاَةِ يَضَعُ الْيُمْنَى عَلَى الْيُسْرَى وَتَعْجِيلُ الْفِطْرِ وَالاِسْتِينَاءُ بِالسَّحُورِ  

Yahya related to me from Malik from Abu Hazim ibn Dinar that Sahl ibn Sad said, "People used to be ordered to place their right hands on their left forearms in the prayer." Abu Hazim added, "I know for sure that Sahl traces that back to the Prophet ﷺ."  

أَنَّهُ قَالَ كَانَ النَّاسُ يُؤْمَرُونَ أَنْ يَضَعَ الرَّجُلُ الْيَدَ الْيُمْنَى عَلَى ذِرَاعِهِ الْيُسْرَى فِي الصَّلاَةِ قَالَ أَبُو حَازِمٍ لاَ أَعْلَمُ إِلاَّ أَنَّهُ يَنْمِي ذَلِكَ