How do we know that spiritual exercises are beneficial for Christians?

Spiritual exercises are beneficial for Christians primarily because they foster genuine dependence on God and protect them from complacency in their faith. As noted, without the challenges of doubt and fear, believers may become entangled in a system of mere formality devoid of true power. The exercises compel the soul to seek the Lord earnestly, reflecting the importance of a living faith rather than a lifeless orthodoxy. This necessity is emphasized in the thought that exercises lead the believer continually to the throne of mercy, where they can experience the fullness of God's grace.

Additionally, these spiritual trials preserve believers from the danger of having a nominal faith, which has led many astray. They ensure that believers remain vigilant and yearning for Christ, the source of true life, rather than settling for an empty profession of faith. Though sometimes painful, these experiences keep believers engaged in the reality of their need for salvation and ongoing sanctification.