Worldliness is whatever any culture does to make sin seem normal and righteousness to be strange. When we imbibe the Zeitgeist (the spirit of the age) of worldliness, then we feel strange trying to think Christianly and to act according to the Bible’s mandates. That is, when we think the world’s thoughts after it and do not think God’s thoughts after Him, we will not be motivated to do the things that God wants us to do, but we will only feel comfortable acting in a manner that fits into the world’s way of doing things. This is why Christians who cease going to church begin to feel more and more comfortable in the world and less and less comfortable in the church. For the same reason, this is why regular attendance at church is so important. At church we worship by hearing God’s Word, praising God, praying, partaking of the Lord’s Supper and fellowshipping, all of which encourages believers and convinces them that they indeed are the ones who are normal and that the world is strange before God’s eyes. Believers need to encourage one another that, from the biblical perspective, it is normal for God’s people to reflect Christ and his behavior and not the world’s.
—Gregory K. Beale,We Become What We Worship: A Biblical Theology of Idolatry, 300