Charles H. Spurgeon on Psalms 109:4

Persecuted saints are men of prayer, yea, they are as it were made up all of prayer. David prayed before; but, oh, when his enemies fell a persecuting of him, then he gave himself up wholly to prayer. Oh, then he was more earnest; more fervent, more frequent, more diligent, more constant, and more abundant in the work of prayer! When Numa, king of the Romans, was told that his enemies were in arms against him, he did but laugh at it, and answered, "And I do sacrifice"; so when persecutors arm themselves against the people of God, they do but divinely smile and laugh at it, and give themselves the more up to prayer. When men arm against them, then they arm themselves with all their might to the work of prayer; and woe, woe to them that have armies of prayers marching against them. —Thomas Brooks.