A.W. Tozer emphasizes the necessity of purity of heart for spiritual fruitfulness, using the analogy of cherry trees affected by parasites that hinder their growth. He reflects on the importance of a pastor's role in nurturing a healthy vineyard, urging that a church should embody the purity and righteousness that Christ desires. Tozer prays for believers to align with Christ's high priestly prayer, striving for a heart that is pure and capable of producing genuine spiritual experiences. He warns against the futility of emotional experiences devoid of true righteousness, asserting that sound conduct is foundational for authentic spirituality.

On our farm in Pennsylvania there were cherry trees which were attacked by little parasites of some sort. A parasite would get into a little branch, pierce the bark and exude a gum. Then the branch would get a knot on it and bend. All over the trees were those little bent places with gummy knots. After two or three years, those cherry trees would not bloom. If they did, the blooms usually dropped early and the cherries did not come to fruition. If the blooms did not drop early, the cherries would be flat and undeveloped or only red on one side. My father was not too interested in fruit. He was interested in cattle, horses and grain. If my father had known how he could have protected those trees before they got into that wretched condition and properly sprayed or treated them, he could have gotten rid of the worms and bugs and saved the trees and fruit. I believe that a pastor who is content with a vineyard that is not at its best is not a good husbandman. It is my prayer that we may be a healthy and fruitful vineyard and that we may be an honor to the Well Beloved, Jesus Christ the Lord, that He might go before the Father and say, "These are mine for whom I pray, and they have heard the Word and have believed on Me." I pray that we might fit into the high priestly prayer of John 17, that we would be a church after Christ's own heart so that in us He might see the travail of His soul and be satisfied. In order for us to be a vine like that, there must be basic purity. Each one must have a great purity of heart. I believe that there are no emotional experiences that do not rest upon great purity of heart. No one can impress me or interest me in any kind of spiritual manipulation if his or her heart is not pure--even if it is raising the dead. Sound righteousness in conduct must be at the root of all valid spiritual experience.