What happened on the cross? Did Jesus kill the devil? If so, why is the devil very active in this world, and why can he do whatever he wants to do? Why he is "the master of this world"? How can he interfere to ruin God's work? Many times I feel he is stronger than God.
Our Lord and Savior Jesus Christ gave us salvation on the cross. Through His suffering and death, we were healed and given the grace to believe in Him and follow Him through His commandments and the Holy Sacraments for the forgiveness of sins. The devil is a spirit. Spirits do not die. Our Lord Jesus Christ destroyed the power over death, which Satan clutched. Thus, we rejoice with confidence, proclaiming,
"O Death, where is your sting? O Hades, where is your victory?" (1 Corinthians 15:55).
The devil is weak. Life here is not intended to be a continuation of paradise. We are in exile but through the Crucifixion we have been reconciled with God and have hope for our eternal salvation. However, for us Christians, Emmanuel means "God is with us." His peace is an unworldly peace engulfing us by His grace. Though outwardly we may suffer, but our inner peace is from God. "Peace I leave with you, My peace I give to you; not as the world gives do I give to you. Let not your heart be troubled, neither let it be afraid" (John 14:27). The devil can instigate trouble, but he has no real power. We must not allow moments of weakness to justify the devil's conspiracy to trip us in his snares.