Blessed is the one who does not walk in step with the wicked or stand in the way that sinners take or sit in the company of mockers, but whose delight is in the law of the Lord, and who meditates on his law day and night.
Psalm 1:1-2 (NIV)
Are these verses telling us not to associate with sinners (unbelievers)? Not really, our Lord Jesus hung around with the sinners of his day (some of them were tax collectors) but he did it to redeem them, not to gain their support or wisdom. There is a difference.
Instead, the Bible tells us not to walk with ungodly men or hang around with those who mock God. This involves avoiding any guiding influence that might direct our ways of life toward ungodliness. As Christians, we cannot expect to make spiritual progress if we seek guidance, follow lifestyles, or make plans with unbelievers (2 Corinthians 6:14). We are to rejoice in the Word and ways of the Lord. We should apply biblical truths to our lives, daily focusing on the Word, studying it and meditating on it.
It is true that none of us are perfect when it comes to the Word of God, but we should continually strive for that end, until we reach it. Remember that God calls us to live righteous lives - to be set apart, holy.