Afflictions evidence to ourselves, and manifest to others, the reality of grace. When we suffer as Christians, exercise some measure of that patience and submission, and receive some measure of these supports and supplies, which the Gospel requires and promises to believers—we are more confirmed that we have not taken up with mere notions; and others may be convinced that we do not follow cunningly devised fables. Afflictions likewise strengthen us—by the exercise our graces. As our limbs and natural powers would be feeble if not called to daily exertion—so the graces of the Spirit would languish, without something which was provided to draw them out to use.
This is exercising oneself unto godliness (I Tim.4:7).