Matthew Poole and continuators on Isaiah 56:3

3 Neither let the son of a stranger , that hath joined himself to the LORD speak, saying, The LORD hath utterly separated me from his people, neither let the eunuch say, Behold, I am a dry tree .

The stranger, as the son of man is the same with the man, v. 2. the Gentile, who by Birth is a stranger to God, and to the Common-Wealth of Israel.

That hath turned from dumb Idols to the living God, and to the true Religion: for such shall be as acceptable to me as the Israelites themselves, and the partition-wall between Jews and Gentiles shall be taken down, and Repentance and Remission of sins shall be preached and offered to men of all Nations.

Who is here joined with the stranger, because he was forbidden to enter into the Congregation of the Lord, Deut. 23. 1. as the stranger was, and by his barrenness might seem no less than the stranger to be cast out of Gods Covenant, and cut off from his People, to whom the blessing of a numerous Posterity was promised. And under these two Instances he understands all those persons, who either by Birth, or by any Ceremonial Pollution, were excluded from the participation of Church priviledges, and so he throws open the door to all true Believers without any restriction whatsoever.

A sapless and fruitless Tree, accursed by God with the curse of barrenness, which being oft threatned as a Curse, and being a matter of Reproach among the Jews might easily occasion such discouraging thoughts as are here expressed.