Also the sons of the foreigner, that join themselves to the LORD, to serve him, and to love the name of the LORD, to be his servants, everyone that keeps the sabbath from defiling it, and takes hold of my covenant; Even them will I bring to my holy mountain, and make them joyful in my house of prayer: their burnt offerings and their sacrifices shall be accepted upon my altar; for my house shall be called a house of prayer for all people. (Isaiah 56:6-7)