There is nothing so capable of banishing the inherent tendencies of licentiousness from our soul, and of driving away those active memories which rebel in our flesh and produce a turbulent flame, as to immerse oneself in the fervent love of instruction, and to search closely into the depth of the insights of divine Scripture.
When a man’s thoughts are totally immersed in the delight of pursuing the wisdom treasured in the words of Scripture by means of the faculty that gains enlightenment from them, then he puts the world behind his back and forgets everything in it, and he blots out of his soul all memories that form images embodying the world. Often he does not even remember the employment of the habitual thoughts which visit human nature, and his soul remains in ecstasy by reason of those new encounters that arise from the sea of the Scripture’s mysteries.
And again, if the mind swims on the surface of the waters, that is, of the sea of the divine Scriptures, and its perceptions cannot fathom the great depth so as to be able to grasp all the treasures in its deep, yet even this practice in itself, by the power of its fervent love, will suffice the mind firmly to pinion its thoughts by a single thought of wonder, and to prevent them from hastening toward the body’s nature, as one of the Godbearing Fathers said. And this [he says] is because the heart is feeble and cannot sustain the evils that it encounters from inner and outer warfares. And you know that an evil [bodily] thought is oppressive. If the heart is not occupied with study, it cannot endure the turbulence of the body’s assault.
St Isaac of Nineveh, Ascetical Homily 1, 17-19.
From this translation by Holy Trasnfiguration Monastery.