The necessity of daily asking ourselves the above question, is only learned through practice, combined with an earnest desire of detecting and destroying the "beam in our own eye."
A Christian Science student may never expect to turn traitor towards Christ or the Truth, but nevertheless how often it is done; more often, of course, unconsciously than consciously; and only through a severe self-examination can we hope to detect and correct such errors.
It may not be necessary to point out the various ways in which the Truth is daily betrayed; everybody finds that out easily enough, but the root of such evil, or self-love, self-will, self-justification and ignorance, must be uncovered before it can be eliminated.