The Prophet ﷺ said, "I have been commanded to prostrate on seven bones, on the forehead," and he pointed with his hand to his nose, "the hands, the knees, and the feet."
قال النبي ﷺ: أمرت أن أسجد على سبعة أعظم: على الجبهة. وأشار بيده على أنفه، واليدين، والركبتين، والرجلين.
Bukhari narrated it in the Book of Adhan (812), and Muslim narrated it in the Book of Salah (490), both from the hadith of Wahib, from Abdullah bin Tawus, from his father, from Ibn Abbas, and he mentioned it.His statement, "and he pointed with his hand to his nose," is evidence for those who say that it is sufficient in the sajdah for the nose to touch the ground, even though Ibn Munzir reported that the companions were in consensus that sujud on the nose alone does not suffice.However, Abu Hanifa and some of the companions of Malik said that if one confines himself to whichever of the two he wishes, that is valid. Imam Ahmad said that one must prostrate on both the forehead and the nose together, because they are one organ. The majority held that placing the forehead alone on the ground suffices, and if one adds the nose to it, that is recommended.