A new life begins with changing the way we think. God's gift of repentance through the living message gives a new life in Christ. The apostles had experienced this gift of life. God's gift of life can only lead to success. God's gift of life is not from any human origin.
Human efforts fail.
For if their purpose or activity is of human origin, it will fail. The apostles realized the source of their strength. They were trusting in the enabling strength and power of God to carry them beyond the threats of Satan. There was an awareness the religious courts were not fighting the apostles, they were fighting God. This makes it a joy to offer up praise to God as we suffer for him and with him.