A song of ascents.
This phrase indicates that Psalm 133 is part of the Songs of Ascents, a collection of Psalms (120-134) traditionally sung by Hebrew pilgrims as they ascended to Jerusalem for the three major feasts: Passover, Pentecost, and Tabernacles. The ascent is both a physical journey to the elevated city of Jerusalem and a spiritual journey towards God. The Songs of Ascents emphasize themes of unity, worship, and the anticipation of meeting God in His holy city.

Of David.
Attributed to King David, this Psalm reflects his experiences and desires for unity among the tribes of Israel. David, as a unifying king, brought together the northern and southern tribes, establishing Jerusalem as the political and spiritual center. His authorship lends authority and historical context, as David himself experienced the challenges and blessings of unity among God's people.

Behold,
This word serves as a call to attention, inviting the reader or listener to consider the significance of what follows. It emphasizes the importance of the message and encourages reflection on the beauty and value of unity.

how good and pleasant it is
The terms "good" and "pleasant" suggest both moral and experiential benefits. "Good" aligns with God's creation, as seen in Genesis 1, where God declares His creation "good." "Pleasant" indicates a sense of delight and satisfaction, suggesting that unity is not only right but also enjoyable. This duality underscores the holistic blessing of harmony among believers.

when brothers live together in harmony!
The term "brothers" refers to the Israelites, the twelve tribes descended from the sons of Jacob. In a broader sense, it applies to all believers as spiritual siblings in the family of God. The concept of living "together in harmony" implies more than mere coexistence; it suggests a deep, abiding peace and cooperation. This unity is a reflection of God's nature and His desire for His people, as seen in the New Testament call for unity in the body of Christ (Ephesians 4:3). The imagery of harmonious living also points to the future Messianic kingdom, where perfect unity will be realized under the reign of Jesus Christ, the Prince of Peace.

It is like fine oil on the head
The imagery of oil in the Bible often symbolizes blessing, consecration, and the presence of the Holy Spirit. In ancient Israel, anointing with oil was a significant ritual, especially for priests and kings, signifying their divine appointment and empowerment. The "fine oil" suggests purity and richness, indicating a special and sacred anointing. This phrase evokes the anointing of priests, particularly Aaron, the first high priest, as described in Exodus 30:22-30, where God commands Moses to anoint Aaron and his sons with a specially prepared holy anointing oil.

running down on the beard
The oil running down the beard signifies abundance and overflow, suggesting that the blessings of God are not just sufficient but plentiful. The beard, particularly in ancient Near Eastern culture, was a symbol of maturity and dignity. The image of oil flowing down the beard emphasizes the thoroughness of the anointing, covering the individual completely. This can be seen as a metaphor for the unity and harmony among God's people, as the blessings of God flow from the head (leadership) to the rest of the body (community).

running down Aaron’s beard
Aaron, as the first high priest, represents the priesthood and the mediatory role between God and His people. The mention of Aaron specifically ties this anointing to the priestly office, highlighting the sacredness and divine approval of his role. This connection to Aaron also points to the idea of unity among the people of Israel, as the priesthood was central to their worship and communal identity. The anointing of Aaron is a type of Christ, who is our High Priest, anointed by God to mediate a new covenant (Hebrews 4:14-16).

over the collar of his robes
The oil flowing over the collar of Aaron's robes signifies the completeness of the anointing, covering him from head to toe. The robes of the high priest were intricately designed and held great significance, as described in Exodus 28. They symbolized holiness, service, and the beauty of God's presence. The oil covering the robes indicates that the anointing affects not just the individual but also their role and function within the community. This can be seen as a foreshadowing of the anointing of believers in Christ, who are called to be a royal priesthood (1 Peter 2:9), living lives that reflect God's holiness and unity.

It is like the dew of Hermon
Mount Hermon is a significant geographical landmark in the northern part of Israel, known for its height and abundant dew. The dew of Hermon is symbolic of refreshment and life-giving moisture in an otherwise arid region. This imagery suggests a divine blessing that brings vitality and sustenance. In biblical times, dew was essential for agriculture, especially in dry seasons, symbolizing God's provision and care. The comparison to Hermon's dew emphasizes the richness and abundance of God's blessings.

falling on the mountains of Zion.
Zion, often synonymous with Jerusalem, represents the spiritual center of Israel and the dwelling place of God among His people. The imagery of Hermon's dew falling on Zion suggests a supernatural unity and blessing that transcends geographical boundaries. This symbolizes the unity and harmony among God's people, as the dew brings life to the mountains. Zion is also a prophetic symbol of the coming kingdom of God, where peace and unity will prevail. The connection between Hermon and Zion underscores the idea of God's blessings flowing from one part of His creation to another, uniting them in His purpose.

For there the LORD has bestowed the blessing
The phrase indicates a divine act of giving, where God Himself is the source of blessing. In the context of Psalm 133, this blessing is closely tied to unity among believers, which is pleasing to God. The concept of blessing in the Old Testament often involves prosperity, peace, and divine favor. This particular blessing is not just temporal but has eternal significance, pointing to the ultimate fulfillment of God's promises to His people.

of life forevermore.
This phrase speaks to the eternal nature of the blessing God bestows. It suggests not only a quality of life that is abundant and full but also one that is everlasting. In the New Testament, eternal life is a central theme, often associated with the salvation and life found in Jesus Christ. The promise of life forevermore connects to the hope of resurrection and eternal communion with God. It reflects the ultimate goal of God's redemptive plan, where believers are united with Him in eternal life, a theme echoed in passages like John 10:10 and Revelation 21:4.