2 Corinthians 1:21-22

Now it is God who establishes and confirms us [in joint fellowship] with you in Christ, and who has anointed us [empowering us with the gifts of the Spirit]; it is He who has also put His seal on us [that is, He has appropriated us and certified us as His] and has given us the [Holy] Spirit in our hearts as a pledge [like a security deposit to guarantee the fulfillment of His promise of eternal life].