Now this I have to disagree with. Then Christ Himself states that He shall lose NONE that has been given Him... which NONE = 0... not 0 + 1.... Then that would contradict what Christ said, if in fact, a true believer in Christ could depart from the faith. It's impossible as Christ says Himself.
These are self profession Christians, in the church, participating and claiming Christ, but they have not accepted him in their heart. They have a head knowledge of Him, but no heart transplant that God gives us at the new birth. If in fact, even ONE saved person in Christ, could depart from the faith, the Christ would be a liar. Why do you think it states that many will cast our demons and do these miracles, but yet Christ says depart? Because He never "KNEW" them to begin with. They were never HIS.
Joh 6:37 All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out.
Joh 6:38 For I came down from heaven, not to do mine own will, but the will of him that sent me.
Joh 6:39 And this is the Father's will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day.