Al-Bara' described to us (the nature of prostration). He placed his hands (palms), reclined on his knees, and raised his hips; he said: This is how the Messenger of Allah ﷺ used to prostrate himself.  

وَقَالَ هَكَذَا كَانَ رَسُولُ اللَّهِ ﷺ يَسْجُدُ  

Anas reported the Messenger of Allah ﷺ as saying; Adopt a moderate position when prostrating yourselves, and see that none of you stretches out his forearms(on the ground) like a dog.  

أَنَّ النَّبِيَّ ﷺ قَالَ اعْتَدِلُوا فِي السُّجُودِ وَلاَ يَفْتَرِشْ أَحَدُكُمْ ذِرَاعَيْهِ افْتِرَاشَ الْكَلْبِ  

When the Prophet ﷺ prostrated himself, he kept his arms so far away from his sides that if a lamb had wanted to pass under his arms, it could have done so.  

أَنَّ النَّبِيَّ ﷺ كَانَ إِذَا سَجَدَ جَافَى بَيْنَ يَدَيْهِ حَتَّى لَوْ أَنَّ بَهْمَةً أَرَادَتْ أَنْ تَمُرَّ تَحْتَ يَدَيْهِ مَرَّتْ  

I came to the Prophet ﷺ from behind. I saw the whiteness of his armpits and he kept his arms away from his sides and raised his stomach (from the ground).  

أَتَيْتُ النَّبِيَّ ﷺ مِنْ خَلْفِهِ فَرَأَيْتُ بَيَاضَ إِبْطَيْهِ وَهُوَ مُجَخٍّ قَدْ فَرَّجَ بَيْنَ يَدَيْهِ  

When the Messenger of Allah ﷺ prostrated himself, he kept his arms far away from his sides so much so that we took pity on him.  

حَدَّثَنَا أَحْمَرُ بْنُ جَزْءٍ صَاحِبُ رَسُولِ اللَّهِ ﷺ أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا سَجَدَ جَافَى عَضُدَيْهِ عَنْ جَنْبَيْهِ حَتَّى نَأْوِيَ لَهُ  

when one of you prostrates himself, he should not stretch out his forearms( on the ground) like a dog and he should join both of his thighs.  

أَنَّ النَّبِيَّ ﷺ قَالَ إِذَا سَجَدَ أَحَدُكُمْ فَلاَ يَفْتَرِشْ يَدَيْهِ افْتِرَاشَ الْكَلْبِ وَلْيَضُمَّ فَخِذَيْهِ