Second Samuel details the many military exploits of King David (see, for example, 2 Sm 8:1-14), who was divinely appointed as commander of God’s people (see 1 Sm 13:14).  Other biblical books tell how God sometimes gave instructions for the Israelites to go to war (see, for example, Jgs 1:1-2).  In light of such passages, it is difficult to justify a strictly pacifist position — that is, the stance that war is always forbidden to God’s people.

Christian pacifist communities often insist that the New Testament standard replaces the Old Testament example in this regard.  They cite, for example, Jesus’ gospel command to “offer no resistance to one who is evil” (Mt 5:39), and his warning that “all who take the sword will perish by the sword” (See Mt 26:51-54).

Nevertheless, the New Testament also contains St. Paul’s statement that the civil state “does not bear the sword without purpose; it is the servant of God to inflict wrath on the evildoer” (Rom 13:4).  The natural law allows for self-defense, and Scripture commands us to defend and “rescue the lowly and poor; / [and] deliver them from the hand of the wicked” (Ps 82-3-4).  In this light, Christians have reasonably argued that sometimes war is justifiable — in fact, that justice and charity may demand our engagement in war to defend both our own people and the innocent victims of aggressors in other nations.

As the Catechism teaches, then, on occasion war can indeed be just, and public authorities can “impose on citizens the obligations necessary for national defense.”  But “the strict conditions for legitimate defense by military force require rigorous consideration” (2310 and 2309, emphasis in the original).  For instance, all other means to resolve the issue must have proven futile (see 2309 for a summary of all of the conditions).

Meanwhile, the Church urges all people, especially governments, to work for peace — not just the avoidance of war, or the uneasy balance of power between adversaries, but the creation of just conditions that lead to social and political tranquility.  “Blessed are the peacemakers, / for they will be called children of God” (Mt 5:9).

Related Scripture:

Texts Cited: Jgs 1:1-2  •  1 Sm 13:14  •  2 Sm 8:1-14  •  Ps 82:3-4  •  Mt 5:39; 26:51-54  •  Rom 13:4
General: Nm 21:14  •  Jgs 4:4-16  •  Ps 20:8; 29:11; 34:15; 46:9-10; 55:22; 68:31; 120:6-7; 122:6-7; 144:1  •  Prv 12:20; 20:18  •  Eccl 3:8  •  Is 2:4; 9:4-6; 57:19; 60:17  •  Zec 9:10  •  Mt 24:6  •  Lk 21:9  •  Rom 14:19  •  Jas 3:18
Catechism of the Catholic Church: 2263-2267  •  2302-2317  •  2321  •  2327-2330