Ephesians 1:13 In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise.
Official documents have a seal put on them, which proves they are authentic, or have the authority of the government behind them. Since you represent Jesus, His authority stands behind you when you are operating in His behalf, see John 14:12-14.
The person who attacks the sealed child of God who is living for the Lord, attacks the authority of heaven which endorses you as genuine. Another value of being sealed by the Holy Spirit, is that you can have His guidance, help and protection.
Believers become the property of God, and are sealed by the Holy Spirit. Your responsibility is to maintain this seal by frequently having your mind renewed through studying the Word and prayer, see Romans 12:1, 2.
