عَنْ أَنَسِ بْنِ مَالِكٍ رَضِيَ اللَّهُ عَنْهُ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَ: ((اعْتَدِلُوا فِي سُجُودِكُمْ وَلَا يَفْتَرِشْ أَحَدُكُمْ ذِرَاعَيْهِ افْتِرَاشَ الْكَلْبِ، أَتِمُّوا الرُّكُوعَ وَالسُّجُودَ، فَوَاللَّهِ إِنِّي لَأَرَاكُمْ مِنْ بَعْدِي أَوْ مِنْ بَعْدِ ظَهْرِي إِذَا رَكَعْتُمْ وَإِذَا سَجَدْتُمْ))
It is narrated from Sayyiduna Anas bin Malik, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: Maintain moderation in prostrations, no person should spread his arms like a dog, complete the bowing and prostration, by Allah! When you bow and prostrate, I see you from behind my back.