A New Creation Through God’s Spirit of Power

What is the connection between the gift of the Holy Spirit at Pentecost and the Ten Commandments? What roles do the spiritually circumcised heart and the crucifixion of the old man and the creation of the new man play in all of this? Who or what is the new man, and what is the function of God's Holy Spirit of power in the re-creation of converted Christians? And how can we be sure that we will be in God's Kingdom?