“Blessed are the pure in heart, for they shall see God” (Mt 5:8). This is a great promise, my brothers, and something to be desired with all one’s heart. For to see in this way is to be like God, as John the Apostle says, “Now we are all sons of God, but it has not yet been made clear what we shall be. For we know that when it is made clear we shall be like him, for we shall see him as he is” (1 Jn 3:2). This vision is eternal life (Jn 12:50), as Truth himself says in the Gospel, “This is eternal life, that they should know that you alone are the true God, and him whom you have sent, Jesus Christ” (Jn 17:3).
Hateful is the blemish which deprives us of this blessed vision. Detestable is the neglectfulness which causes us to put off the cleansing of the eye, For just as our bodily vision is impeded either by a humor within, or by dust from outside entering the eye, so too is our spiritual vision disturbed by the desires of our own flesh or by worldly curiosity and ambition. Our own experience teaches us this, no less than the Sacred Page, where it is written, “The body which is corruptible weighs down the soul and the earthly habitation oppresses its thoughts” (Wis 9:15). But in both it is sin alone which dulls and confuses the vision; nothing else seems to stand between the eye and the light, between God and man. For while we are in this body we are in exile from the Lord (2 Cor 5:6).
That is not the body’s fault, except in that it is yet mortal (Rom 7:24); rather it is the flesh which is a sinful body (Rom 6:6), the flesh in which is no good thing but rather the law of sin reigns (Rom 7:23, 25). Meanwhile the bodily eye (Gn 27:1), when the mote is no longer in it (Mt 7:4) but has been taken or blown away, still seems dark (Mt 7:3ff.), as he who walks in the spirit and sees deeply often experiences (2 Cor 12:18; Gal 5:16). For you will cure a wounded limb quickly by withdrawing the sword, but only if you apply poultices to heal it. For no one should think himself cleansed because he has come out of the cesspit. No, rather let him realize that he stands in need of a thorough washing first. Nor must he be washed only with water; he needs to be purged and refined by fire so as to say, “We have passed through fire and water, and you have brought us to a resting place” (Ps 65:12). “Blessed are the pure in heart, for they shall see God” (Mt 5:8). “Now we see through a glass darkly, but hereafter face to face” (1 Cor 13:12). Then truly our faces will be completely clean, so that he may present them to himself shining, without stain or wrinkle (Eph 5:27).
Bernard of Clairvaux
“On Conversion”, XVII, 30.