But if you cannot see what good exercises have done you, can you not see what evil they have kept you from? They mainly kept you from being entangled in a worldly system; they have preserved you from resting in the form without the power, and kept you from that notional dead-letter faith which has ruined so many thousands. (This extract was taken from a letter to a friend.) Without exercises you could do without a revealed Christ, without manifested pardon of sin, without the love of God being shed abroad in your heart by the Holy Spirit.
And here most are, who are not exercised—resting in “a name to live,” and in the doctrine without the experience. But, being sick, you need a physician; being guilty, you need mercy; and being a sinner, you need salvation; and all this, not in word and name, but in reality, and divine revelation and application. Your exercises give you errands to the throne of mercy, and make you see in Christ and his precious gospel what otherwise would neither be seen nor cared for.
At the same time, it would be wrong to rest in exercises as marks and evidences of grace. Thirst is good as preparatory for water; hunger is good as antecedent to food; but who can rest in thirst or hunger? Without them, water and food are not desired; so, without exercises, Christ, the Water and Bread of life, is not desired nor longed for. But these exercises are meant to quicken longing desires after Christ, and eventually make him very precious.