Albert Barnes Commentary Job 36:18

"For let not wrath stir thee up against chastisements; Neither let the greatness of the ransom turn thee aside." — Job 36:18 (ASV)

Because there is wrath - That is, the wrath of God is to be dreaded. The meaning is that if Job persevered in the spirit which he had manifested, he had every reason to expect that God would suddenly cut him off. He might now repent and find mercy, but he had shown the spirit of those who were rebellious in affliction, and if he persevered in that, he had nothing to expect but the wrath of God.

With his stroke - With his smiting or chastisement; compare Job 34:26.

Then a great ransom cannot deliver thee - Margin, “turn you aside.” The meaning is that a great ransom could not prevent him from being cut off. On the meaning of the word ransom, see the notes at Job 33:24.

The idea here is not that a great ransom could not deliver him “after” he was cut off and consigned to hell (which would be true), but rather that once he had manifested a spirit of insubmission a little longer, nothing could save him from being cut off from the land of the living. God would not spare him on account of wealth, or rank, or age, or wisdom. None of these things would be a “ransom” in virtue of which his forfeited life would be preserved.