Can the devil tempt a Christian? Certainly (1 Peter 5:8). Can the devil use a Christian to tempt someone else? Certainly. There is an ally of Satan inside each Christian; it is the sinful nature (Romans 7:15-25).
These are reasons why the Bible instructs us to “resist the devil” (James 4:7). Thanks be to God that Jesus Christ successfully completed his mission of conquering the devil (1 John 3:8) and that he equips us to be successful in our daily skirmishes with the devil (Ephesians 6:10-17).