Why does the New Testament use war as a metaphor for Christian life and mission?

The background must be the Old Testament - like what we find in 1 Samuel 11.

Podcast Summary:

War is a grim reality, but the Bible tells us the real battle isn’t fought with swords—it’s a spiritual fight, where truth, righteousness, and the gospel are our weapons. In 1 Samuel 11, Israel faces a crisis as the ruthless Nahash besieges Jabesh-Gilead, demanding their submission. The people panic, not turning to God or even their newly anointed king, Saul—because they hadn’t yet accepted him as their leader. But when the Spirit of God rushes upon Saul, everything changes. A disregarded king becomes the instrument of salvation, and Israel, once fearful, rallies to victory—not by their strength, but by God’s power. This Old Testament battl ...