Psalm 133: How Good and Pleasant

"Behold, how good and how pleasant it is for brethren to dwell together in unity! It is like the precious ointment upon the head, that ran down upon the beard, even Aaron's beard: that went down to the skirts of his garments; as the dew of Hermon, and as the dew that descended upon the mountains of Zion: for there the LORD commanded the blessing, even life for evermore."

Flowing down

Two images of something flowing down: anointing oil running from Aaron's head down his beard to his robe (Exodus 29:7; 30:30; the high priest pictured), and the heavy dew of Mount Hermon, Israel's highest mountain, falling on Zion far to the south. The verb "ran down" (yored) is used three times. Hermon's dew reaching Zion is a poetic image of blessing coming down from above, not a weather report.

"Brethren" and reception

"Brethren dwelling together" may mean family members sharing an inheritance (Deuteronomy 25:5), the tribes gathered at festival, or the whole people. The opening, "Hinneh mah tov u-mah na'im," is a well-known Jewish song. The heading names David (Vulgate "Canticum graduum David"). The heading "A Song of degrees" (Vulgate "Canticum graduum") marks it as one of the fifteen Songs of Ascents (Psalms 120–134; see Psalm 120 for the possible meanings).