The attempt by a radical Islamic terrorist to take down an American jetliner on Christmas day should remind each of us that the price of liberty is eternal vigilance. I am not just speaking of physical liberty, but of spiritual liberty as well.

Those who plot to destroy and take captive often choose to strike when others are relaxing and off guard. In 1962 when the Soviet Union's communist leaders decided to erect a wall to divide the city of Berlin, they chose a Sunday morning knowing U.S. officials would be at the beach or in their weekend homes. It worked by catching America off guard and delaying a reaction.

I would bet the news of the Christmas day attack on the Northwest Airlines jet bound for Detroit took some time to register and sink in with most people. It was the last thing most would have expected on this holiday. That is likely why the alleged suicide bomber, Umar Farouk Abdulmutallab, chose that day.

There is a spiritual lesson here for all of us. The Bible describes Satan as a roaring lion stalking about seeking victims to devour (1 Peter 5:8). Satan is a spirit, also called the "prince of the power of the air" by the apostle Paul. Satan knows no boundaries of time. He regards no day. He is always working, seeking a victim to ensnare and bring captive to his will.

You and I must never forget this truth. Guard your thoughts, your heart and your mind. We are told in the same passage to "resist him, steadfast in the faith" (1 Peter 5:9). It takes an active and constant vigilance to guard against the spiritual attacks Satan launches at those he targets.

In the wake of this latest terrorist attack, homeland security officials are reexamining screening measures for all airline passengers. Stocks of companies that manufacture sophisticated devices to detect bombs hidden on people are going up. Vigilance and detection are keys to maintaining the security of a free people.

The decade that ends tonight has been dominated by a war of terror. What erupted on 9/11 had been developing for years and was ignored by many. Government officials failed to "connect the dots" to understand the grave threat to American life and security. Even after this tragic episode, most have gone about pursuing a normal life, not fully counting the cost of the kind of war being fought. No American leader ever fully called on the nation to embrace the kind of war footing that would seriously grapple with the threat at hand. It was a decade of lost opportunity and appeasement in the face of tyranny. The Christmas day attack is a reminder America has enemies who seek to destroy its way of life.

A Christian should take a larger spiritual warning from this incident and be reminded of the adversary, Satan the devil, who never takes a vacation. He is constantly waging war on God's Kingdom of truth and righteousness. Do not retreat in fear or cowardice. God's promise, power and protection are available to keep us from falling prey. Call on God for help. Maintain a vigilant stance. Do not give Satan any place to dwell in your life. That is the price of spiritual liberty.

Remember, evil takes no holiday. Keep watching.