133:2 The writer compared brotherly unity to the oil that Moses poured over Aaron's head when he anointed him as Israel's first high priest (Lev. 8:12). That oil flowed down over his head and beard, down onto the robe and breastplate that bore the names of the 12 Israelite tribes. As the consecrating oil covered everything and bound it together so unity among believers makes them acceptable to God as a kingdom of priests.
133:3 Mt. Hermon to the north of Israel was the highest mountain in the land. As such it enjoyed unusually heavy dew. Dew was a great blessing in the parched land of Israel. As the dew freshened and invigorated Mt. Hermon, so the unity of believing Israelites would refresh and invigorate Mt. Zion as they gathered for worship there.
When unity characterizes believers, they can perform priestly work with divine approval and they can enjoy God's blessings of refreshment and fertility.
