In Phil 4:1, Paul bookends the admonition he began in 1:27 while laying a foundation for more specific instruction to follow with the command to “Stand firm thus in the Lord.” To “stand firm” is a military term that Paul uses in Ephesians and in 1 Corinthians. Paul is presenting His instruction in terms of spiritual warfare. The commands in his admonition show us how to stand firm and hold our ground against the opposition of the world, false teachers and the temptation to give in to strife with the body of Christ. In all such opposition, the Evil One is the agent of influence (cf. Eph 6:12). We must resist him, steadfast in the faith (1 Pet 5:9).