From the earliest days after the Ascension of Jesus Christ to the Almighty Father, the Apostles were under constant attack and came to see and speak of the Church as an army of soldiers who were engaged in a spiritual battle against Satan and evil.

The Apostles immediately face great persecution

After being commanded by Jesus Christ in the Great Commission to take up the mission to convert the entire world (Mt 28:16-20, CCC 2), the Apostles immediately face a great and fierce battle as their mission is violently opposed by both the Jewish leaders and the Romans, and they are persecuted. Reflecting upon Jesus Christ’s great battle during His public ministry and their own struggles, the Church on earth takes on the mindset of warriors for God.

The Apostles come to see the Church as an army of holy soldiers

From the earliest days, the Church became known as the Church Militant (from Latin, militans, meaning, “being a soldier, performing a military service”) because Jesus definitely revealed the reality that life on earth is a continuous spiritual battle of life and death (CCC 405-409, 1426, 1707, 2015, 2516).

Jesus constantly battles Satan

All of the writers of the New Testament (except the short Letter of St. Jude) explicitly carry on Jesus’ war against Satan, confirming the reality of the ongoing spiritual warfare of the Church Militant by specifically and repeatedly referencing the great enemy is Satan (or devil, the evil one): Matthew (Mt 4:1-11, 12:26, 13:19, 38-39, 16:23, 25:41), Mark (1:13, 3:23-26, 4:15, 8:33), Luke (Lk 4:1-4, 8:12, 10:18, 11:18, 13:16, Acts 5: 3, 10:38, 13:10, 26:18), John (Jn 6:70, 8:44, 13:2, 27, 17:15, 1 Jn 2:13-14, 3:8-10, 3: 12, 5:18-19, Rev 2:9, 10, 13, 24, 3:9, 12:9, 12, 20:2, 10), Peter (1 Pet 5:8), Paul (Rom 16:20, 1 Cor 5:5, 7:5, 2 Cor 2:11, 11:14, 12:7, Eph 4:27, 6:11, 16, 1 Thes 2:18, 2 Thes 2:2, 1Tim 1:20, 3:6-7, 5:15, 2 Tim 2:26, Heb 2:14), and James (3:15, 4:7).

St. Paul urges men to fight in the Spiritual Battle

Paul confirms the early Church Militant understood the spiritual battle in which men must engage by the militaristic metaphors he included in his New Testament letters: refers to disciples as “soldiers” (1 Cor 9:7, Phil 2:25, 2 Tim 2:3-4, Philem 1:2); refers to the “battle” and “war”of the spiritual life (Rom 7:23, 1 Cor 14:8, 2 Cor 10:3-4, 1 Tim 1:18); urges men to “fight” (2 Cor 7:5, 1 Tim 6:12, 2 Tim 4:7); urges men to put on “the armor of God” (Eph 6:11-17); reveals that Catholic men are spiritually branded like soldiers (Gal 6:17; CCC 1295); describes Jesus’ words in war-like terms, call it a “two-edged sword” (Heb 4:12).

Revelation confirms Christ returns to complete the Spiritual Battle

In the Book of Revelation, the culminating book of the Bible, John confirms the reality of the great and violent spiritual battle and the Second Coming of Jesus Christ: Christ opens the Seven Seals, revealing the “bow with which to conquer”, the “great sword”, and destruction by the sword (Rev 6); the Seven Trumpets which signify the commencement of the great destruction on earth (Rev 8:6-9:11:19); the Great Dragon (Satan) seeks to attack the woman and kill the child (Rev 12:1-6); the great war in Heaven (Rev 12:7-10); Satan makes war against the Woman’s children (Rev 12: 13-17), the Seven Bowls of God’s wrath (Rev 16); Christ, the Heavenly Warrior, leads the armies of Heaven to violently defeats the Beast (Rev 19:11-21); Satan is seized and cast into the abyss of Hell (Rev 20:1-3). 

The Church continues to be the Catholic Church Militant

Though there are some in the Church today who downplay or avoid the violent life-and-death spiritual battle in which men are either received into Heaven as Saints or condemned as the Damned in Hell, Christ’s Holy Catholic Church on earth continues to recognize the severity of the spiritual battle of the Catholic Church Militant and calls every Catholic man to engage in the spiritual battle against Satan and evil. 

The Catechism emphasizes the Spiritual Battle

Consistent with the teachings of Jesus Christ that have been embraced for two millennia, the current Catechism of the Catholic Church, Christ’s Church Militant continues to confirm the nature of the spiritual war in which Catholic men must engage using militaristic terms: “warfare” (CCC 162), “warriors” (CCC 1090), “soldiers” (CCC 1295), “fight”, “combat” or “battle” (CCC 256, 409, 978, 1458, 1889, 2592, 2752, 2805, 2849); “struggle” (CCC 1426, 1707, 1820, 1839, 2530, 2549, 2857). The Church also continues to emphasize and honor the great “martyrs” who have died in the spiritual battle to build the Church as witnesses for Jesus (CCC 852, 957, 1173, 2113,  2473-2474, 2642).

The Church confirms Christ’s final triumph

Until His Second Coming, the Church Militant will remain “under attack by the evil powers” and men will “groan and travail” (CCC 671-672) and face the ultimate trial (CCC 675-676)  under the final assault by the powers of evil until Christ’s final triumph, meaning, “success in battle” (CCC 677, 680-681) which will occur at His Second Coming.