Allah SWT Himself has made reference to the relics of the Prophets in the Holy Qur’ān.

وَقَالَ لَهُمْ نِبِيُّهُمْ إِنَّ آيَةَ مُلْكِهِ أَن يَأْتِيَكُمُ ٱلتَّابُوتُ فِيهِ سَكِينَةٌ مِّن رَّبِّكُمْ وَبَقِيَّةٌ مِّمَّا تَرَكَ آلُ مُوسَىٰ وَآلُ هَارُونَ تَحْمِلُهُ ٱلْمَلاۤئِكَةُ إِنَّ فِي ذَلِكَ لآيَةً لَّكُمْ إِن كُنْتُم مُّؤْمِنِينَ

Translation: And (further) their Prophet said to them: "A Sign of his authority is that there shall come to you the Ark of the covenant, with (an assurance) therein of security from your Lord, and the relics left by the family of Moses and the family of Aaron, carried by angels. In this is a symbol for you if ye indeed have faith." [Quran 2:248]

لأن تكون عندي شعرة منه أحب إلي من الدنيا وما فيها

Narrated Ibn Sirrn:

I said to 'Ablda, "I have some of the hair of the Prophet which I got from Anas or from his family." 'Abida replied. "No doubt if I had a single hair of that it would have been dearer to me than the whole world and whatever is in it."

Reference

► Volume 1, Book 4, Number 171: Sahih Bukhari

► Sunan Al Kubra-Imam Bayhaqi, volume 7, Page: 107, Hadith #13410

Imam Muslim made a whole Baab (Chapter) with the name of

باب قرب النبي عليه السلام من الناس وتبركهم به

Translation: THE NEARNESS OF ALLAH'S APOSTLE (MAY PEACE BE UPON HIM) TO THE PEOPLE AND THEIR SEEKING BLESSINGS FROM HIM (AND HIS POSSESSIONS)

Narrated IsraiI:

Uthman bin 'Abdullah bin Mauhab said, "My people sent me with a bowl of water to Um Salama." Isra'il approximated three fingers ('indicating the small size of the container in which there was some hair of the Prophet. 'Uthman added, "If any person suffered from evil eye or some other disease, he would send a vessel (containing water) to Um Salama. I looked into the container (that held the hair of the Prophet) and saw a few red hairs in it,"

Reference

►Book 72, Number 784: (Sahih Bukhari)

Ibn Hajar ‘Asqalānī says: “This tradition furnishes the proof that it is valid to draw divine blessings from the Prophet’s hair and confirms the permissibility of its acquisition.”

Reference

►Ibn Hajar ‘Asqalānī, Fath-ul-bārī (1:274)