While Ellen White's writings emphasize the importance of individual preparation for the close of probation and the coming of Christ, and warn against spiritual unpreparedness, the exact statement "Not one in 20 church members will be ready at the close of probation" does not appear in the provided search results. Her writings do convey a strong sense of urgency and the need for deep, faithful searching of heart, stating that "The work of preparation is an individual work. We are not saved in groups. The purity and devotion of one will not offset the want of these qualities in another.... Every one must be tested, and found without spot or wrinkle or any such thing" (Sons and Daughters of God 355.4). She also warns about the perilous condition of those who become "weary of their watch, turn to the attractions of the world" and are found "sleeping" when probation closes (Homeward Bound 337.2). While a specific numerical ratio like "one in 20" is not found, the overarching message is that many who profess faith will not be ready due to a lack of earnest preparation and a focus on worldly things.