What is the ruling on celebrating the birth of the Prophet, peace and blessings be upon him, and holding such celebrations on every occasion as an act of gratitude to God, or for weddings or the seventh day after a child's birth, and what is the response to those who say it is to remind people of the Prophet's biography?

Celebrating the birth of the Prophet, peace and blessings be upon him, or any other birth, was not part of the guidance of the Prophet, peace and blessings be upon him, nor the guidance of his companions. Worship is based on divine injunction, and what Allah and His Messenger have legislated. Any act of worship that the Prophet, peace and blessings be upon him, left despite the presence of a cause and the absence of a barrier, then abandoning it is a Sunnah (definition), and doing it is a reprehensible innovation. Reminding people of the Messenger's biography, peace and blessings be upon him, is done by teaching and explaining it in mosques and educational institutions, not by reciting it on a specific night or hour with the accompaniment of forbidden string instruments, or concluding it with seeking help and directing supplication to other than Allah.