It was in the death and resurrection of Jesus that God's full power was revealed to man. After Jesus died and rose again, God's power was shown to the authorities and powers that dominated the realms. No man ever went down to hell and came up again, except Jesus (Acts 2:31-32). This event shocked the rulers of the world so much that it spun them off their axis of comprehension (1 Corinthians 2:8). It was the wisdom and power of God at work in its rare form (1 Corinthians 1:24).
The cross of Jesus is where the wisdom of God was further revealed to the rebellious dark powers that rule the cosmos. Even though they revere God's sovereignty, they somehow always try to resist it and argue against it as if to prove a point. However, once again, the immortal, invincible God proved His Kingship and Lordship over every force in existence.
That same power is what God wants you to live by. He wants you to master the powers and authorities in heavenly places because He has put them all under your feet by His mighty power (Ephesians 1:22). The Lord has placed you in a position of authority, so you can be an expression of His power, showing the entire creation His wisdom, power, and authority through your life every day.

Lord, I pray You to give me a comprehensive understanding of the power of the cross. I pray You to enlighten the eyes of my understanding and give me the grace to enjoy all that You've given me freely. Through Your mighty power, You have given me the grace to always triumph over every principality and power that opposes me. By the power of the cross, You have given me life and the power to live above sin and every limitation of the flesh. In Christ, I'm saved, I'm free, and I'm delivered now and forever. Amen.