Who really is "the meanest motherfucker in the valley"?

In Renny Harlin's 1999 Deep Blue Sea LL Cool J gives a great badass interpretation of the classic 23rd Psalm of the old testament:

Yeah, though I walk through the valley of the shadow of death, I shall fear no evil, for thou art with me. Thy rod and thy staff, they comfort me. Surely goodness and mercy shall follow me all the days of my life. Because I carry a big stick and I'm the meanest motherfucker in the valley! Two sharks down, Lord! One demon fish to go! Can I get an Amen?

Now when recently rewatching Brian De Palma's 1989 vietnam treatment Casualties of War I noticed that Sean Penn's Sgt. Meserve gives a similar rendition:

Yeah, though I walk through the valley of evil, I shall fear no death ... Cause I'm the meanest motherfucker in the valley!

And I wondered if there is any information that Deep Blue Sea was actually referencing Casualties of War in this regard or at least took inspiration for this quote from there, or if there is an older "colloquialization" of psalm 23 those two quotes were independently based on?

Best Answer

This is a (misattributed, according to Wiki) George S. Patton quote:

Yea, though I walk through the valley of the shadow of death I shall fear no evil, because I am the meanest son-of-a-bitch in the valley.

(This was a widely published anonymous derivative of Psalm 23 which arose in the early 1970s on wall-posters, plaques and t-shirts, with an early variant also reading "Yea, though I walk through the valley of the shadow of death I shall fear no evil: for I am the meanest bastard in the valley"; much cruder variants, with less clear association with the original biblical passages have since emerged on the internet, and in very recent years have begun to be attributed to Patton. There are no historical sources indicating he ever actually said anything resembling this.)

A version with MF is one of the more popular "cruder variants". It's possible that these movies popularized it, but it's a chicken and egg thing. There's also an MF version in a 1991 book about Vietnam by Major Bruce H. Norton. 'Carry a big stick' is inspired by a different US leader, of course.