Christ's question asks the reason for this all but universal dishonesty of having two weights and measures for faults. He would have us ponder on the cause, that we may discover the remedy. He would have us reflect, that we may get a vivid conviction of the unreasonableness of the practice. There is nothing in the fact that a fault is mine which should make it small in my judgment; nor, on the other hand, in the accident that it is another's, which should make it seem large. A fault is a fault, whoever it belongs to, and we should judge ourselves and others by the same rule. Only we should be most severe in its application to ourselves, for we cannot tell how much our brother has had, to diminish the criminality of his sin, and we can tell, if we will be honest, how much we have had, to aggravate that of ours. So the conscience of a true Christian works as Paul's did when he said 'Of whom I am chief,' and is more disposed to make its own motes into beams than to censure its brother's.
The reason, so far as there is a reason, can only lie in our diseased selfishness, which is the source of all sin. And the blindness to our 'beams' is partly produced by their very presence. All sin blinds conscience. A man with a beam in his eye would not be able to see much. One device of sin, practised in order to withdraw the doer's attention from his own deed, is to make him censorious of his fellows, and to compound for the sins he is inclined to by condemning other people's.
Verse 42 teaches that the conquest of our own discovered evils must precede efficient attempts to cure other people's. To pose as a curer of them while we are ignorant of our own faults is, consciously or unconsciously, hypocrisy, for it assumes a hatred of evil, which, if genuine, would have found first a field for its working in ourselves. An oculist with diseased eyes would not be likely to be a successful operator. 'Physician, heal thyself' would fit him well, and be certainly flung at him. A cleansed eye will see the brother's mote clearly, but only in order to help its extraction. It is a delicate bit of work to get it out, and needs a gentle hand.
Our discernment of others' faults must be compassionate, not to be followed by condemnation nor self-complacency but by loving efforts to help to a cure. And such will not be made unless we have learned our own sinfulness, and can go to the wrongdoer in brotherly humility, and win him to use the 'eye-salve' which our conduct shows has healed us.
II. The second compressed parable of the two trees springs from the former naturally, as stating the general law of which verse 42 gives one case, namely, that good deeds (such as casting out the mote) can only come from a good heart (made good by confession of its own evils and their ejection). It is often said that Christ's teaching is unlike that of His Apostles in that He places stress on works, and says little of faith. But how does He regard works? As fruits. That is to say, they are of value in His eyes only as being products and manifestations of character. He does not tell us in this parable how the character which will effloresce in blossoms and set in fruits of goodness is produced. That comes in the next parable. But here is sufficiently set forth the great central truth of Christian ethics that the inward disposition is the all-important thing, and that deeds are determined as to their moral quality by the character from which they have proceeded.
Our actions are our self-revelations. The words are not to be pressed, as if they taught the entire goodness of one class of men, so that all their acts were products of their good character, nor the unmingled evil of another, so that no good of any kind or in any degree is in them or comes from them. They must be read as embodying a general truth which is not as yet fully exemplified in any character or conduct.