The classic battle between good and evil.
"Finally, be strong in the Lord and in his mighty power...take your stand against the devil's schemes. For our struggle is not against flesh and blood, but against...this dark world and...forces of evil..." Ephesians 6:10-12 (NIV)
To withstand satanic attacks, we must depend on God's strength to fight for us. Satan is vicious--he is constantly battling against all who are on God's side. God has provided his Holy Spirit to dwell in us.
Are you still trying to fight on your own strength?