David wrote this psalm after he became the king of Israel. During the time of the judges, the tribes of Israel often fought against each other for their individual interests. But with David as their king, all the tribes were united under one common head. Because of this, some commentators say that David penned Psalm 133 to exhort the Israelites to unite and live in love. This psalm can also teach us how wonderful it can be and what rich blessings we will receive if we all live as one. But how do we reach the state of unity David describes?
We must have pure love for one another. David compares living in unity with the precious oil running down the head, beard, and garment of Aaron. Before they were allowed to minister before the Lord, Aaron and his descendants were anointed with oil. This oil represents our love for our brethren. Like the oil used to anoint the Levitical priests, our brotherly love must be holy and pure. And just as the Levitical priests must be anointed before serving the Lord, we must possess pure love for one another before God accepts our service.
We must also serve as a source of blessings for one another. David compares living in unity to the dew of Hermon. Hermon is a high mountain located north of Israel that receives large amounts of water and serves as the source of moisture for the lands below. Without the waters and dew from Hermon, life on the mountains of Zion would wither away. Similarly, we must serve as a source of encouragement and nourishment for our brethren so that they will not weaken and fall away.
Let us all strive to live in unity so that we may receive Godâ€™s blessing of life forevermore and experience "how good and how pleasant it is for brethren to dwell together in unity!"