Isaiah 56:6-7

And foreigners who bind themselves to the LORD to minister to him, to love the name of the LORD, and to be his servants, all who keep the Sabbath without desecrating it and who hold fast to my covenant – these I will bring to my holy mountain and give them joy in my house of prayer. Their burnt offerings and sacrifices will be accepted on my altar; for my house will be called a house of prayer for all nations.’