Now this I say and testify in the Lord, that you must no longer walk as the Gentiles do, in the futility of their minds. (ESV)
Have you ever thought about the way that you walk? I am reminded of Monty Python's "Ministry of Silly Walks" sketch. The way that we walk is important to God. And, of course, we are not talking about the way that we physically walk, but rather the life that we live. Our actions should be different than the actions of those who do not know the Lord. Paul refers to Gentiles as those who do not have a relationship with God through Jesus Christ.
What is interesting to note here is that the reason the Gentiles walk wrongly is that they are wrong in their thinking. The pagan mind elevates his own reasoning. Man does have the ability to observe certain things in the universe. But, their understanding of what they have observed only shows how little they really understand. I think of Stephen Hawking, considered by many to have been one of the smartest men alive. Here is a quote by him:
“We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.” (From the German magazine Der Spiegel [October 17, 1988])
His brilliant Gentile mind led him to a belief that we are just an advanced breed of monkeys. And if we are monkeys then where is the incentive to behave in a moral way that treats our brother or sister with love or kindness? The fact is that Gentile thinking leads to all kinds of harm to mankind and foolish immoral behavior. You cannot walk properly if your thinking is godless. Listen to the Apostle Paul's words to the church at Corinth:
1 Corinthians 3:19–20
 For the wisdom of this world is folly with God. For it is written, “He catches the wise in their craftiness,”  and again, “The Lord knows the thoughts of the wise, that they are futile.” (ESV)
How are you walking? Check your thinking. As Christians we walk differently because we think differently. We are not monkeys, but rather God's special creation. We live for his glory, and that gives us meaning and purpose.