But this poem would be in the running on my list of most brilliantly poetic verses in the whole of the TaNaKh, and is all the more powerful in its reverberating brevity.
Here is a comment from Great Texts of the Bible, edited by Reverend James Hastings and published in 1916:
Nowhere has the nature of true unity—that unity which binds men together, not by artificial restraints, but as brethren of one heart—been more faithfully described, nowhere so gracefully illustrated, as in this short ode. True concord, we are here taught, is a holy thing, a sacred oil, a rich perfume, which, flowing down from the head to the beard, from the beard to the garment, sanctifies the whole body. It is a sweet morning dew, which falls not only on the lofty mountain-peaks but on the lesser hills, embracing all and refreshing all with its influence.
The preservation of this unity was the object of the selection of one place to which the tribes should go up on pilgrimage three times a year. And the intercommunion with each other which the pilgrimages fostered was certainly one of the chief means by which the unity of feeling and sentiment was kept up among the scattered members of the nation century after century.
Here is another lovely comment, from the College Press Study Bible Textbook Series:
The stay in the sacred city was not long, but it was an abiding while it lasted: it brought brethren face to face who had never before seen each other; and, sweeping away prejudices and misunderstandings, cementing holy friendships by sacred service and song and by the giving and receiving of domestic courtesies, made the participants realise how truly they were brethren.
וכי שני זקנים היו לאהרן ואת אמרת הזקן, זקן?! אלא כיון שראה משה את השמן יורד על זקן אהרן, היה שמח כאלו על זקנו ירד.
Did Aharon, then, have two beards, that it is mentioned twice here? Rather, when Moshe saw the annointing oil running down upon the beard of Aharon, he rejoiced as though it had run down upon his own beard.
How good. It is possible that this speaks of Moshe Rabeinu, z"l, as the torah is called after his name; and this is "how good." There is no "good" other than Torah. And "how pleasant" is Aharon the Priest, who would walk to bring (to put) peace between a person and his friend, between man and wife, and whose pleasantness in our days increases peace. Brothers dwell together. And according to the secret (kabbalah), it is known that the Holy Blessed One's name is "how" (mah). And the Ar"i z'l wrote that the kinship is also called "how." As it is written in secret "how (what) are we, how are our lives." And this is a hint to "how good and how pleasant it is" Holy Blessed One "that brothers dwell together." And thus it is said, how good and how pleasant. And our rabbis said, every place that it says "hineh" - here/behold - it means happiness. As it is said, "here he is coming forth towards you, and he sees you and is happy in his heart." And thus is is written, "how good an how pleasant" - what great happiness when God communes. ...
