When I was a young kid, my father exhorted me to never back down in any fight, to stand up and always defend myself. Now, whether or not this is the right thing to do is a whole other issue. However, it seems as though Paul is relaying a very similar message to Timothy, only of a spiritual manner rather than a physical one. He explicitly tells Timothy that there WILL in fact be spiritual fights throughout our lives. He tells us not to back down but rather to fight by taking hold "of the eternal life to which [we] were called". This only concurs with the passage found in Ephesians 6 concerning the "full armor of God".
We must always strive to live with an eternal perspective on life rather than a worldly one. It's very easy to get caught up in the world as we live in the flesh. If we keep our sights focused upon Christ, the battles before us will always be won. But, the minute we begin to lose that focus, the prince of this world will seemingly always prevail. So, don the full armor of God, pray, keep focused, and get ready to "fight the good fight of the faith".
Gregory B. Dill