It is tragically sad how many take James out of context to make it say something that it does not say....
James compares the mental assent of faith by a man to the devils which believe (not in JESUS for saving faith, but rather that there is indeed a god (THE GOD) and the majority of the world, in some form or fashion, believes in a god, some god, many gods, but the very mental assent these people make that there is a god (THE GOD) does not equate to saving faith.
The key to understanding James point about the evidence of a saving faith is found in the words (SHOW ME) and goes to the very root of what James is saying....
What good does it do to say to someone who is hungry or cold...be filled and warmed if no coat or food is given? ABSOLUTELY NOTHING......JUST as a MERE MENTAL ASSENT that there is a GOD does NOTHING in the realm of saving a man.
The whole address of JAMES is AIMED at the ability of MEN to SEE in a MAN that invisible, biblical saving FAITH that actually goes beyond a MERE MENTAL ASSENT that their is indeed a GOD (THE GOD)
IT HAS absolutely NOTHING to do with what is required for a MAN to be saved by biblical FAITH.
JESUS is the prime example of how ALL of this bears out......HE was not made a SON of GOD by HIS IMMERSION, HE WAS NOT MADE a SON of GOD by the many wonderful works and miracles that he performed.....
HE WAS BORN the SON OF GOD BY BIRTH through the POWER of the SPIRIT......everything beyond that WAS PROOF of who he was.
JESUS was clear.....WHAT MUST I DO said the LOST MAN.....JESUS SAID, "THIS IS THE WORK of the HEAVENLY FATHER, THAT YOU BELIEVE on HIM WHOM HE HAS SENT."
NOT a MERE mental ASSENT that there is a GOD, but RATHER that the SON of GOD died on the cross to save you from your sins and that GOD has raised him up the 3rd day for YOUR JUSTIFICATION.
MEN are SAVED eternally by FAITH into the GOSPEL MESSAGE.....BAPTISM (Immersion) is the 1st ACT of obedience and the PUBLIC testimony of said FAITH........IT IS a WORK of RIGHTEOUSNESS and states to the world....I AM DEAD with CHRIST, I AM BURIED with CHRIST and I AM RESURRECTED with CHRIST as a NEW CREATION, BORN A SON OF GOD by the SPIRIT and INCORRUPTABLE SEED.
ANYTHING, ALL things beyond the INITIAL saving faith is the proof in the pudding if you will. THE whole concept of faith without works is dead IS APPLICABLE to the MENTAL ASSENT compared to the same belief in god by the devils and is not applicable unto genuine saving faith that eternally saves, justifies, seals and sanctifies positionally before GOD!
BEFORE anyone uses the words MUST HAVE...refer to the BOLDED above!!