Isaiah 56:6-7

Also the sons of the foreigner who join themselves to the LORD to serve Him, and to love the name of the LORD, and to be His servants, to everyone who keeps from polluting the Sabbath and takes hold of My covenant, even them I will bring to My holy mountain and make them joyful in My house of prayer. Their burnt offerings and their sacrifices shall be accepted on My altar; for My house shall be called a house of prayer for all people.