The Messenger of Allah ﷺ said, "When one of you prays, he should not spread out his forearms on the ground the way a dog spreads its paws."
حدثنا محمد بن فضيل حدثنا الأعمش عن أبي سفيان
قال رسول الله ﷺ إذا صلى أحدكم فلا يفترش ذراعيه افتراش الكلب
Its isnad is sahih, mentioned previously at 13353.