God regulates and dispenses his grace in such a manner, that, as long as believers remain in this world, he always trains them to patience, and does not in every instance answer their prayers, therefore he brings them back to doctrine; as if he had said, “Thou wilt indeed find that I am kind to thee in various ways; but. there is no happiness which will be of greater importance to thee, or which thou ought to desire more earnestly, than to feel that I am present by ‘the word’ and ‘the Spirit.’” Hence we infer that this is a most valuable treasure of the Church, that he has chosen for himself a habitation in it, to dwell in the hearts of believers by his Spirit, and next to preserve among them the doctrine of his gospel. - Calvin, Commentary on Isaiah 59:21