Like many others on the morning of September 11, 2001, I turned on the television to see the World Trade Center on fire. Was it an accident? But when the second plane crashed into the other tower, it became clear that this was no accident. It was a terrorist attack on the United States. Then to hear that the Pentagon had been hit . . . and then to see the World Trade Center collapse . . . what seemed like the impossible unfolded before our very eyes.

The inevitable question arises after a tragedy like this: "Why?" Some have even asked, "Why did God allow this to happen?" But God did not do this at all. This was done by the wicked heart of man, because deep inside, humanity is twisted and sick spiritually. As Jeremiah 17:9 says, "The heart is deceitful above all things and desperately wicked; who can know it?" (NKJV).

When God created humans, He gave us something called a free will. This means that we all have the ability to choose right or wrong. You might say that free will is our greatest blessing, and in other ways, it is our greatest curse. We were uniquely created in the image of God Himself and have been given this ability to choose. But we usually make the wrong choices.

If you don't believe the human heart is wicked, then visit the Yad Vashem in Israel, a museum dedicated to the memory of the six million Jews who were senselessly slaughtered by Hitler and the Nazis.

If you don't believe the human heart is wicked, then recall the reactions when the news of the attacks reached Osama bin Laden, who thanked "almighty Allah," and some Palestinians, who rejoiced and danced in the streets.

If you don't believe the human heart is wicked, then take a long look at what you saw on September 11, 2001.

Some well-meaning but misguided people might say these events must have been God's will. I disagree. It wasn't God who did this. It was Satan, working in concert with wicked man, who did this. The Bible tells us that the whole world lies under the sway of the wicked one (1 John 5:19). Satan did this through wicked people who were bent on destruction.

What should we do as we see horrible things happening? Jesus gives us some important answers in Luke 21. He says: "Now when these things begin to happen, look up and lift up your heads, because your redemption draws near" (v. 28 NKJV). It's a reminder that He is coming soon.

In light of that fact, how should we be living? We find the answer a few verses later: "But take heed to yourselves, lest your hearts be weighed down with carousing, drunkenness, and cares of this life, and that Day come upon you unexpectedly" (v. 34).

This means that if you are waiting for the return of the Lord, you need to be living a godly life. You don't want to be doing something that is displeasing to God. Instead, you want to have your life right with Him.

In His Word, God has given us His warning about these things. Each of us must ask ourselves: Am I doing anything that I would be ashamed to be doing if Jesus Christ were to come back tonight? If the answer is yes, then you need to stop doing it right now. The Bible says that He will come again to those who are looking for Him.

Is it the end of the world as we know it? Only God knows that. But I will tell you this much: It was the end of many people's world on September 11, 2001. What if you died tonight? What if Jesus came back today?

That is why you want to be ready. That is why you need to be sure you're right with God. You don't know when death will come or when Jesus will return. The Bible says that we don't know "the day or the hour the Son of Man is coming" (Matthew 25:13). Be ready to go. All of the time.

Note: If you want to know how you can be ready, please see God's Plan of Salvation.