NOTES for Mat 7:1-5
The beam and the speck are things of the same nature, but of a different "order." And it may seem that, because of its size, the beam in the eye keeps a person from seeing anything at all. But the point is precisely that the one who carries it in his eye is blind only with respect to himself. With respect to others, it works like a magnifying glass, helping him make out the smallest offenses of others. And then the desire is born to help another person get rid of the speck (see Matt. 7:4).
Yet a person suffering from a severe form of some disease cannot cure another person of the same disease, even if it has only just begun. Besides, with such a "magnifier" it is easy to confuse the sizes and prepare a saw instead of a scalpel...
Only a person who is already healthy, who has passed through the pain of healing, because when Someone takes a beam out of your eye it hurts, can help another. That is why Christ says: "First take the beam out of your own eye, and then you will see clearly how to take the speck out of your brother's eye" (Matt. 7:5).