Albert Barnes Commentary Isaiah 56:6

"Also the foreigners that join themselves to Jehovah, to minister unto him, and to love the name of Jehovah, to be his servants, every one that keepeth the sabbath from profaning it, and holdeth fast my covenant;" — Isaiah 56:6 (ASV)

Also the sons of the stranger - (see the note at Isaiah 56:3). The conditions on which they should be admitted to the same privileges are specified, and are the following:

1. They were to join themselves to the Lord (see the note at Isaiah 56:3).
2. This should be with a purpose to serve him. Their aim and design should be to keep his commandments and to do his will.
3. They were to love the name of the Lord; that is, to love Yahweh himself, for the name of the Lord is often used as denoting the Lord himself.
4. They were to keep his sabbaths (see the notes at Isaiah 56:4).
5. They were to take hold of his covenant (see the notes at Isaiah 56:4).

On these conditions the sons of the foreigner were to be admitted to all the privileges of the children of God, and to be united with all who love and serve him.