Isaiah 48:2

For they call themselves of the holy city,.... The city Jerusalem, so called because the temple, the place of divine worship, was in it, the residence of the Holy One of Israel: they valued themselves, not only upon their being of the family of Jacob, and of the tribe of Judah, but that they were inhabitants of Jerusalem, the holy city; as many now call themselves fellow citizens with the saints, and of the household of God, when they are strangers both to God and his people in the experimental knowledge of things:

and stay themselves upon the God of Israel; professed to trust in the Lord, and lean upon him, and rely upon his power and providence, his mercy and goodness, and expect all needful things from him, renouncing all confidence in the creature; and yet at the same time acted an hypocritical part, their faith was feigned: see Micah 3:11.

The Lord of hosts is his name; whom they professed to be their God and Father, their Lord and Husband, their Saviour and Redeemer; who has all power in heaven and in earth, and does according to his will in both worlds, having the hosts of angels and armies of men at his command, and therefore so called.