“The Devil is in the Details”
Ironically, the idiom “the devil is in the details” derives from the earlier phrase, “God is in the details,” expressing the idea that whatever one does should be done thoroughly; i.e. details are important. (J. Bartlet)
Why or who changed it seems to be unknown but somewhere around 1975 was when anyone saw in print “The Devil is in the Details” and for whatever reason it was quickly accepted as the primary idiom.
Could it possibly be that it is difficult to pay attention to all the details of a specific activity or event? More than likely; however, it seems that giving the idiom a negative connotation gives the participant permission to be satisfied with just skimming the surface of any endeavor.
Instead it might be more beneficial to use the prior idiom. Especially when it comes to Martial Arts training! Focusing on the details of any move, technique, exercise, etc. tends to lead the practitioner to greater levels of success. Without a doubt, the working through repetition after repetition, on some little nuance of a Martial Arts action may seem tedious but it is that attention to detail that leads to participant to a comfort level of executing the action.
In our “instant gratification” influenced culture it is challenging, to say the least, to get participants enthusiastic about being patient and spending time developing their skills.