133:1 See how good and how pleasant it is for brothers to live together in unity!
133:2 It is like the precious oil on the head, that ran down on the beard, even Aaron’s beard; that came down on the edge of his robes;
133:3 like the dew of Hermon, that comes down on the hills of Zion: for there Yahweh gives the blessing, even life forever more.
The verse centers on "good", "pleasant", "brothers", "live", "together", "unity", "like", and "precious". It is saying that the verse draws attention to "good" and "pleasant", so its meaning should be read from those terms before moving to application.
The local WEB text gives this verse as the immediate unit, so "good" and "pleasant" carries the first interpretive weight. In Psalms context, the local focus is worship, trust, the LORD's kingship, and covenant mercy.
A plain takeaway is to answer the verse's own emphasis on "good" and "pleasant" with trust shaped by these words, not by a vague optimism outside the passage.