1 Corinthians 16:13

A Christian is a soldier, environed and attacked on all sides by enemies. It is his duty to guard against surprise. He should never abandon the post of faith, nor the fortress of the Church, unless he wish to fall an easy prey to his adversaries. He should fight with courage, and after each attack, carefully repair the breaches made by the enemy, that he may be in a condition to sustain fresh attacks by charity, which is the principle, the soul, the life, and heart of our every action.