'Guarantees' in the Bible

"Tell Hezekiah, king of Judah, "This is what the mighty king, the king of Assyria, has to say: What is this "guarantee" that makes you yourself rely on it? Do you really think that guarantees alone can withstand strategy and military strength? On whom are you now depending, that you're rebelling against me?

They have not said to themselves,‘Let’s fear the Lord our God,who gives the rain, both early and late, in its season,who guarantees to us the fixed weeks of the harvest.’