Check out Matthew 7:23 -- note that among the deeds quoted -- explicitly -- is "casting out demons".
There are people who even legitimately believe they have carried out exorcisms (*), who are nonetheless told "I never knew you."
Ergo, it is possible even to be led astray while performing mighty works in His name.(+)
But problematic here is the phrase "I never knew you" which implies these are not those who have fallen away, in contrast to Hebrews 6:6...
(*) whether they have or not is beyond the scope of this post.
(+) Again, whether they *were* really miraculous works of God, dispensed by his Grace for the sake of the recipient of the miracle, or self-deception, or diabolical deception, I dunno. But the people who were involved apparently themselves thought the miracles were genuine.
Nonetheless, let us continue to pray for one another.
Likewise, from the reaction of the individuals mentioned who DID the miracles and casting out demons, they thought that THEY were genuine as well.
They clearly thought that their works made them Christian. Such is the nature of deception.
And it shows that good works aren't what saves one.
WELL PUT.
THX.