Yet Michael the archangel, when contending with the devil he disputed about the body of Moses, durst not bring against him a railing accusation, but said, The Lord rebuke thee. (Jude 9)
This verse is one of the strongest verses supporting the "traditional" view of Satan, namely that the New Testament affirms the existence of an external, supernatural devil, contrary to the perspective of Christadelphians and some other groups. The meaning of this verse is pretty clear: the archangel Michael is disputing about "the body of Moses" (του Μωυσεως σωματος) with "the devil" (τω διαβολω) and this “devil” is clearly an external, supernatural being.
Christadelphians, such as Ron Abel and Duncan Heaster, are forced to engage in the grossest form of eisegesis to explain this verse away in light of the Christadelphian rejection of a supernatural Satan, a doctrine that is to be rejected per the Birmingham Amended Statement of Faith). Heaster, in The Real Devil and Abel in his Wrested Scriptures: A Christadelphian Handbook of Suggested Explanations to Difficult Passages argue that “the devil” refers to a group of disobedient Jews at the time of Joshua in Zech 3(!) The problem is that “the devil” in Jude 9 is a singular, not plural, term. Furthermore, among the many problems against the Christadelphian approaches to this problematic verse (see this paper), perhaps the greatest problem is that the overwhelming majority of scholarship on Jude agree that Jude is quoting an apocryphal work, “The Assumption of Moses,” where the archangel Michael is in a dispute with “the devil” about the body of Moses. Here are vv. 2, 8-10 of this work (notice the similarity between v.8 and Jude 9):
In the book of the assumption of Moses, Michael the archangel, while talking with the devil, says, "For from his Holy Spirit we all were created." And again he says, "From the face of God his Spirit came forth, and the world became." This is the equivalent of "all things through him became" . . ."But when the archangel Michael, contending with the devil, disputed about the body of Moses, he dared not pronounce a reviling judgement upon him, but said, 'May the Lord rebuke you.'" "When on the mountain Moses died, Michael was sent that he might transport the body. Then while the devil was speaking against the body of Moses, charging (him) with murder, on account of striking Egypt, the angel did not hold the blasphemy against him. 'May God rebuke you,' he said to the devil." it says; "Michael the archangel had rendered service to the tomb of Moses. For the devil did not take this back, but bore a complaint, on account of the slaughter of Egypt, as Moses himself, and for this reason did not assent to meet him in honor of the tomb."
Christadelphians are forced to go against the scholarly consensus that Jude is quoting the Assumption of Moses and is affirming the reality of a supernatural devil/Satan in Jude 9. As the Farrar paper (linked above) proves, the arguments of Heaster, Abel, and other apologists (e.g., Peter Watkins, The Devil: The Great Deceiver [1971]) are forced to engage in special pleading and eisegesis to support the non-supernatural Satan doctrine taught by John Thomas in Elpis Israel (1849) and their foundational documents. The “traditional” view of the reality of Satan is based on firm exegetical ground from this verse.