Deuteronomy 19:18

And the judges shall make diligent inquisition: and, behold, if the witness be a false witness, and hath testified falsely against his brother;

Deuteronomy 13:14

Then shalt thou inquire, and make search, and ask diligently; and, behold, if it be truth, and the thing certain, that such abomination is wrought among you;

Deuteronomy 17:4

And it be told thee, and thou hast heard of it, and inquired diligently, and, behold, it be true, and the thing certain, that such abomination is wrought in Israel:

2 Chronicles 19:6-7

And said to the judges, Take heed what ye do: for ye judge not for man, but for the LORD, who is with you in the judgment.

Job 19:16

I called my servant, and he gave me no answer; I intreated him with my mouth.

Treasury of Scripture Knowledge

Summary

And the judges shall make diligent inquisition: and, behold, if the witness be a false witness, and hath testified falsely against his brother;

Bible References

Diligent

Deuteronomy 13:14
Then shalt thou inquire, and make search, and ask diligently; and, behold, if it be truth, and the thing certain, that such abomination is wrought among you;
Deuteronomy 17:4
And it be told thee, and thou hast heard of it, and inquired diligently, and, behold, it be true, and the thing certain, that such abomination is wrought in Israel:
2 Chronicles 19:6
And said to the judges, Take heed what ye do: for ye judge not for man, but for the LORD, who is with you in the judgment.
Job 19:16
I called my servant, and he gave me no answer; I intreated him with my mouth.

General references

Deuteronomy 5:20
Neither shalt thou bear false witness against thy neighbour.
Deuteronomy 25:1
If there be a controversy between men, and they come unto judgment, that the judges may judge them; then they shall justify the righteous, and condemn the wicked.
John 7:51
Doth our law judge any man, before it hear him, and know what he doeth?

King James Version Public Domain