Charles Ellicott Commentary Isaiah 56:2

"Blessed is the man that doeth this, and the son of man that holdeth it fast; that keepeth the sabbath from profaning it, and keepeth his hand from doing any evil." — Isaiah 56:2 (ASV)

That keepeth the sabbath from polluting it ... —It is natural that a devout king like Hezekiah would be an observer of the Sabbath. It is almost certain that the counselors of the young Manasseh (probably the Shebna party), abandoning the religion of Israel in other things, would also disregard this. Accordingly, I interpret the prophet’s teaching as directed against that evil. He declares blessed those who are faithful to the régime of Hezekiah’s reign, even though their alien birth or their condition as eunuchs seemed to exclude them from the polity of Israel (Deuteronomy 23:1–8).