Ephesians 6:15 — The Christian soldier must always be ready and prepared for action because the enemy is always active and his attacks are unexpected. In this sermon on Ephesians 6:15 titled “Mobility,” Dr. Martyn Lloyd-Jones warns to know the devil will do anything to get a Christian down. Paul exhorts believers to have “feet shod with the preparation of the gospel of peace,” meaning there must be a firmness and a mobility, ready and prepared for action. Preparation is the element of mobility, which is of great significance in warfare. Christians must not only watch the enemy, but be ready to counter his moves and meet him where he is attacking. Dr. Lloyd-Jones suggests that this means the Christian cannot be sluggish of spirit, dull, or complacent. Like David, the Christian must be ready to fight in God’s way, no matter how impossible or ridiculous it seems. They must have firmness in strategy: the battle against the devil is the same as it always has been. But they must have mobility and adaptability that is always true to the fundamental teachings of Scripture, because the enemy is always varying his tactics. Christians hold onto old principles, but apply them in a manner that is effective against and adaptable to modern challenges.