Deuteronomy 9:25

25 I lay prostrate before the LORD those forty days and forty nights because the LORD had said he would destroy you.

Read Deuteronomy 9:25 Using Other Translations

Thus I fell down before the LORD forty days and forty nights, as I fell down at the first; because the LORD had said he would destroy you.
"So I lay prostrate before the LORD for these forty days and forty nights, because the LORD had said he would destroy you.
“That is why I threw myself down before the LORD for forty days and nights—for the LORD said he would destroy you.