What is the ruling on seeking blessings from the hair of the Prophet, peace and blessings be upon him, and is it permissible to build a mosque to preserve it?

Seeking blessings from the Prophet's relics (peace be upon him) was permissible during his lifetime, and this is specific to him, and others cannot be analogized to him. Therefore, seeking blessings from the relics of righteous people is an innovation (bid'ah). Currently, there is nothing to prove the existence of any of the Prophet's relics (peace be upon him), and any claim to that effect is incorrect. It is not permissible to build a mosque to house these alleged relics, as this is the practice of the People of the Book who exaggerate in their religion, and the Prophet (peace be upon him) warned against that. The truth and blessing lie in following him and his guidance.