Final answer:
Paul's letters in the New Testament highlight various Christian virtues important for defeating evil, such as faith, hope, and love, as well as unity, humility, and obedience.
Step-by-step explanation:
The qualities by which Paul assures the congregation in Philippi that Satan is defeated are not explicitly outlined in the Bible as a specific list corresponding to this question. However, throughout his epistles, Paul emphasizes various Christian virtues, such as faith, hope, and love, notably outlined in 1 Corinthians 13. It's also clear in the New Testament that Paul stands for unity, humility, and obedience among believers as demonstrated in his letters to various churches. While knowledge, wisdom, and discernment, as well as prayer, righteousness, and perseverance, are important in Christian theology, the expression 'faith, hope, and love', highlighted in 1 Corinthians 13:13, specifically represents key Christian virtues.