This is one of those bursts of feeling the truth and beauty of which every human heart at once acknowledges. Separation, isolation, discord, are unnatural and inhuman.
I. If we wish to appreciate as it deserves this rich gift of God, it is clear that we must look at it in family life. Indeed, the words of the text, however applicable they may be to national and social concord, suggest to us at once the picture not of a nation or of a numerous society, but of a family. We seem to hear the voice of an elder brother, whose heart cannot contain itself for thankfulness at the sight of. peaceful family union. Something has stirred his spirit to detect the greatness of that blessing which has perhaps been interrupted or too long unconsciously enjoyed. At any rate, the beauty of the spectacle must be universally acknowledged. "Behold, how good and joyful a thing it is: brethren, to dwell together in unity!"
II. All unity is a delusion unless it is in some sense a representation, however feeble, of the unity which binds Christ to His Father, and Christ's followers to Himself, that blessed unity for which He prayed on the eve of His agony. When we dwell together in true Christian unity, we are witnesses to the truth of Christ's mission. We have a cause of joy which even the Psalmist could not anticipate. We prove the truth of Christianity. We prove that our beloved Lord and Master is still conquering the world.
H. M. Butler, Harrow Sermons,p. 288.
References: Psalms 133:1. Clergyman's Magazine,vol. xvii., p. 218; R. Tuck, Christian World Pulpit,vol. xiv., p. 281.Psalms 133:3. J. Pulsford, Ibid.,vol. xvii., p. 273, and Old Testament Outlines,p. 151.