The good thing is that when we become believers we have the Holy Spirit deposited within us. It's the mark of God. And not the mark of satan.
2 Corinthians 1:21-22
Now He who establishes us with you in Christ and anointed us is God, who also sealed us and gave us the Spirit in our hearts as a pledge.
Ephesians 1:14
who is given as a pledge of our inheritance, with a view to the redemption of God's own possession, to the praise of His glory.