Because ye have said, We have made a covenant with death, and with hell are we at agreement; when the overflowing scourge shall pass through, it shall not come unto us: for we have made lies our refuge, and under falsehood have we hid ourselves:
Because ye have said - virtually, in your conduct, if not in words.
We have made a covenant with death. There may be a tacit reference to their confidence in their "covenant" with the Assyrians in the early part of Hezekiah's prosperous reign, before that he ceased to pay tribute to them, as if it ensured Judah from evil, whatever might befall the neighbouring Ephraim (Isaiah 28:1). The full meaning is shown by the language ("covenant with death ... hell," or shªowl (H7585)) to apply to all lulled in false security spiritually (Psalms 12:4: contrast Ecclesiastes 8:8, "There is no man that hath power over the spirit to retain the spirit, neither hath he power in the day of death," etc.; Jeremiah 8:11): the godly alone are in covenant with death (Job 5:23; Hosea 2:18; 1 Corinthians 3:22).
When the overflowing scourge - two metaphors; the hostile Assyrian armies like a scourge and an all overwhelming flood.
Shall pass through - namely, through Judea on their way to Egypt, to punish it as the protector of Samaria (2 Kings 17:4).
For we have made lies our refuge. They did not use these words; but Isaiah designates their lying dependencies by their true name (Amos 2:4).