Isaiah 22:25
In that day, saith the LORD of hosts, shall the nail that is fastened in the sure place be removed, and be cut down, and fall; and the burden that was upon it shall be cut off: for the LORD hath spoken it. In that day, saith the LORD of hosts, shall the nail that is fastened in the sure place be removed, and be cut down, and fall; and the burden that was upon it shall be cut off: for the LORD hath spoken it.
The chapter to which the verse belongs is directed against Jerusalem. Within Isaiah 20-22 it stands among prophecies concerning Israel, together with prophecies concerning Assyria, the wilderness of the South, and Idumea. More broadly, it falls within chapters 13-23, the section of Isaiah containing a series of burdens against nations and other peoples.
The larger passage of Isaiah 22:22-25 is connected with the open door of the heavenly sanctuary, where Christ ministers as High Priest before the ark. Through His blood at the mercy seat, pardon and salvation may be sought through Christ's ministry. That invitation remains for those who have not sinned away their day of grace. Seeking that pardon is joined with keeping God's commandments. The verse itself is not explained separately but is included by reference within that appeal.