"Is this vile world a friend to grace,I was listening to a recording of this song this afternoon when I began thinking on this line of the hymn.
To help me on to God?"
—Isaac Watts, from the 3rd stanza of Am I a Soldier of the Cross?
Much of contemporary Christianity lives under the delusion that the "friendship of the world" is not "enmity with God" (James 4:4)—that they can live carnally to whatever extent they wish, while still retaining a satisfactory relationship with their Creator. Nothing could be further from the truth. One cannot love and serve both the world and the Saviour (Matt. 6:24; Luke 16: 13).
On the contrary, the world's obvious goal is to separate you from the Saviour every day of your life (you cannot lose your salvation, of course—this refers to separation from God in your day-to-day walk). The world wants your love. The world will try to deceive you, to get you to think that you can indulge in its many carnal pleasures while loving your Saviour. It will tell you that worldly music, worldly entertainments, worldly speech, worldly thoughts, and worldly churches (and "churches" so called) are all compatible with the Christian walk. It will tell you that a rock song is OK...so long as the words aren't offensive, and perhaps even say something "Christian." It will tell you that unchaste thoughts are reasonable...if you don't go "too far." It will tell you that the vulgar joke really "isn't that bad."
In short, the world will tell you that you can do what you want, and stay in good standing with God. This is deception. The world doesn't want you to be in good standing with God. The world wants your love. And the world won't give it back.
Serve the One Who will love you.