Isaiah 56:6

"Also the sons of the foreigner Who join themselves to the LORD, to serve Him, And to love the name of the LORD, to be His servants-- Everyone who keeps from defiling the Sabbath, And holds fast My covenant--

Surrounding context

56:5 Even to them I will give in My house And within My walls a place and a name Better than that of sons and daughters; I will give them an everlasting name That shall not be cut off.

56:6 "Also the sons of the foreigner Who join themselves to the LORD, to serve Him, And to love the name of the LORD, to be His servants-- Everyone who keeps from defiling the Sabbath, And holds fast My covenant--

56:7 Even them I will bring to My holy mountain, And make them joyful in My house of prayer. Their burnt offerings and their sacrifices Will be accepted on My altar; For My house shall be called a house of prayer for all nations."

Translation and sources