What is the ruling on expanding a mosque at the expense of the tomb of a righteous saint, what is the ruling on the imam's insistence on rebuilding it inside the mosque, and what is the ruling on leaving it if it causes discord among the worshippers and the villagers?

The Prophet, peace and blessings be upon him, forbade taking graves as mosques and praying at them. It is not permissible for a grave to be inside a mosque. If there is a need to expand the mosque in the direction of a grave and the grave is old, there is no harm in removing it and expanding the mosque in that direction. A wall should separate the mosque from the grave, and one must be wary of glorifying the occupant of the grave, directing any form of worship to them, or innovating, such as seeking blessings from them.