Isaiah 19:19

In that day shall there be an altar -An “altar” is properly a place on which sacrifices are offered. According to the Mosaic law, but one great altar was to be erected for sacrifices. But the word ‘altar’ is often used in another sense to denote a place of “memorial;” or a place of worship in general (Joshua 22:22-26. It is clear that Isaiah did not intend that this should be taken “literally,” or that there should be a rival temple and altar erected in Egypt, but his description is evidently taken in part from the account of the religion of the patriarchs who erected altars and pillars and monuments to mark the places of the worship of the true God.