There is so much exegetical evidence against the Christadelphian view of Satan not having ontological existence that their leading defenders have to come up with the most strained, imaginative readings of the biblical texts (see Thomas Farrar’s carefully researched papers responding to the arguments of Duncan Heaster, Jonathan Burke, and other CD authors). One of the best texts against their “no supernatural Devil” position can be seen in Matt 4:1-11 (cf. Mark 1:12-13; Luke 4:1-13) where Christ is tempted by the devil in the wilderness.
The popular Christadelphian view is that the devil here is an external personification of the internal struggle of Jesus. Some Christadelphian authors have tied this into the yetzer hara, "the evil inclination” in Second Temple and Rabbinical literature, notwithstanding the fact that such sources also held to the ontological existence of supernatural evil (Satan and demons). For a book-length treatment, see Ishay Rosen-Zvi, Demonic Desires: Yetzer Hara and the Problem of Evil.
And when the tempter came to him, he said, If thou be the Son of God, command that these stones be made bread. (Matt 4:3)
In this verse, "the tempter" (ο πειραζων) is said to have "come" to Jesus; the verb used here is προσερχομαι which means "to come to." It indicates one person coming to another person, showing that the "tempter" is external to the person of Jesus. This verb is used again in the temptation scene in v.11, "then the devil (ο διαβολος) leaveth him, and, behold, angels came (προσερχομαι) and ministered unto him." In Christadelphian theology, (good) angels have ontological existence, and this verse clearly teaches that angels (personal beings external to Jesus) came to him and ministered to Christ after the devil left Jesus. Only by utilising an inconsistent hermeneutic can one claim that the tempter/devil metaphorically approaches Jesus, but that the angels in v.11 literally approach Jesus.
The external nature of this devil/tempter can also be seen in the fact that he urges Jesus to give him "worship" (προσκυνεω) in v.9. The popular Christadelphian reading forces them to argue that Jesus is tempted by his "evil inclination" to give himself worship! Needless to say, προσκυνεω is rarely used in the whole of Koine Greek literature to have such a reflexive sense!
The only exegetically-valid reading of this scene in the Gospels is that the authors of Scripture accepted the belief in a supernatural, external evil being called "Satan." This flies in the face of the Birmingham Amended Statement of Faith that lists the following as a doctrine to be rejected: "That the devil is a supernatural personal being."