The dew of Mount Hermon

"Behold, how good and how pleasant it is for brethren to dwell together in unity! It is like the precious oil upon the head, running down on the beard, the beard of Aaron, running down on the edge of his garments. It is like the dew of Hermon, descending upon the mountains of Zion; For there the Lord commanded the blessing—Life forevermore." Psalm 133.1-3 

Mount Hermon represents the Mount of Consecration. It is the place where the Lord Jesus was transfigured, glorified and consecrated by God the Father before Peter, James and John. The Jordan River is formed from its sources and it supplies all Israel. It also typifies the Holy Spirit, which sustains the New Israel, the Church, worldwide. Led by the Spirit, King David says that is this Mount the Lord commanded His blessing and eternal life.

Light and blood

"But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin." 1 John 1:7

To walk in the light is to walk according to the Christian discipline. And so we have unity among ourselves and the blood of the Lord Jesus purifies everyone of their sins.

All be one

"...that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us, that the world may believe that You sent Me.."

John 17:21

Just like the Trinity is ONE, so are God's children. Those who are in Christ Jesus live in unity of faith for they have the same Spirit and the same thoughts.

Brothers & Sisters

"Behold, how good and how pleasant it is for brethren to dwell together in unity!" Psalms 133:1

The unity of faith depends in the unity of the Spirit of God. If there's no unity among brothers and sisters, it's because they don't have the same Spirit. In this case, it's better to avoid such kind of 'brothers and sisters'.