Ephesians 1:13-14 (NKJV)
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, 14 who is the guarantee of our inheritance until the redemption of the purchased possession, to the praise of His glory.
Sealed by the Holy Spirit.
When you receive Jesus Christ as your Lord and Savior, you are permanently sealed by the Holy Spirit that dwells within and guides you your entire life. It can't be broken. You are Sealed into salvation through Jesus Christ.
Jesus Christ died on the Cross 2000 years ago to pay for all of our sins and give us the opportunity to receive eternal salvation through His sacrifice.
You are the purchased possession. He loved us so much that He died for us as a sacrifice for our sins to give us the opportunity to receive eternal salvation in Paradise with Him and all other believers.
John 3:16 (NKJV)
16 For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.
You will be redeemed by God one day, if you receive Jesus Christ as your Lord and Savior; once you do this, you are officially sealed as His for eternity!
Romans 10:9-10 (NKJV)
9 that if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved. 10 For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation.