2 Corinthians 1:21-22

But it is God Who confirms and makes us steadfast and establishes us [in joint fellowship] with you in Christ, and has consecrated and anointed us [enduing us with the gifts of the Holy Spirit]; [He has also appropriated and acknowledged us as His by] putting His seal upon us and giving us His [Holy] Spirit in our hearts as the security deposit and guarantee [of the fulfillment of His promise].