The authors of the Old Testament books believed what they were writing was, indeed, from God. A particular phrase was used over 400 times from Genesis to Malachi to prove this. What was this phrase?

The books of the Holy Bible, especially those of the Old Testament, are believed by their respective writers to be from God directly. This was shown in their writings with the use of the phrase "Thus says the Lord". Adding this phrase in their writings or recounts of the events, the authors cement the origin of these book as being genuinely told or gotten from God.

Some examples of such verses are-

1. 2 Chronicles 34: 24

Behold, I will bring evil upon this place and upon its inhabitants, even all the curses that are written in the book which they have read before the king of Judah.

2. Isaiah 7:7

Thus says the Lord God: It shall not stand, neither shall it come to pass.

3. Exodus 4:22

And you shall say to Pharaoh, Thus says the Lord, Israel is My son, even My firstborn.

4. Isaiah 56:4

For thus says the Lord: To the eunuchs who keep My Sabbaths and choose the things which please Me and hold firmly My covenant --