Sahih Muslim , Book 4, Hadith 998 (USC-MSA) ⓘ
This hadith has been narrated by Shu'ba with the same chain of transmitters. And in the hidith transmitted by Ibn Ja'far (the words are): " None of you should stretch out his forearms like the stretching out of a dog."
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَابْنُ، بَشَّارٍ قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، ح قَالَ وَحَدَّثَنِيهِ يَحْيَى بْنُ حَبِيبٍ، حَدَّثَنَا خَالِدٌ، - يَعْنِي ابْنَ الْحَارِثِ - قَالاَ حَدَّثَنَا شُعْبَةُ، بِهَذَا الإِسْنَادِ وَفِي حَدِيثِ ابْنِ جَعْفَرٍ " وَلاَ يَتَبَسَّطْ أَحَدُكُمْ ذِرَاعَيْهِ انْبِسَاطَ الْكَلْبِ " .
also referenced under: Book 4, Hadith 265 (In-Book) & Hadith 493 (Reference)