Blessed are the pure in heart: for they shall see God. Matthew 5:8.

To know what constitutes purity of mind, soul, and body is the highest class of education. Paul the apostle sums up in his letter to Timothy the attainments possible for him, by saying “Keep thyself pure.” ^{46Letter 145, 1897.}

It is the special work of Satan in these last days to take possession of the minds of the youth, to corrupt their thoughts, and inflame their passions…. All are free moral agents. And as such they must bring their thoughts to run in the right channel…. If Satan seeks to divert the mind from this to low and sensual things, bring it back again, and place it on eternal things; and when the Lord sees the determined effort made to retain only pure thoughts, He will attract the mind, like the magnet, and purify the thoughts…. The first work for those who would reform is to purify the imagination. If the mind is led out in a vicious direction, it must be restrained to dwell only upon pure and elevated subjects. When tempted to yield to a corrupt imagination, then flee to the throne of grace, and pray for strength from Heaven. In the strength of God the imagination can be restricted to dwell upon things which are pure and heavenly….

Those who would have that wisdom which is from God, must become fools in the sinful knowledge of this age, in order to be wise. They should shut their eyes, that they may see and learn no evil. They should close their ears, lest they hear that which is evil, and obtain that knowledge which would stain their purity of thoughts and acts. And [they should] guard their tongues, lest they utter corrupt communications, and guile be found in their mouths. All are accountable for their actions while in this world upon probation. All have power to control their actions, if they will. If they are weak in virtue and purity of thoughts and acts, they can obtain help from the Friend of the helpless. Jesus is acquainted with all the weaknesses of human nature, and if entreated, will give strength to overcome the most powerful temptations. All can obtain this strength if they seek for it in humility.^{47Appeal to Mothers, 29-31.}