Revelation 5:6 Then I saw a Lamb, looking as if it had been slain, standing at the center of the throne, encircled by the four living creatures and the elders. The Lamb had seven horns and seven eyes, which are the seven spirits of God sent out into all the earth.
The “seven spirits of God” are also mentioned in 1:4 standing before the throne of God, 3:1 where Jesus is holding the seven spirits and seven stars, and 4:5 linking the seven spirits to the seven burning lamps. Here in 5:6 the seven spirits are linked to the seven horns and seven eyes that the Lamb (Jesus) has.
Accordingly, most interpreters have thought that the seven spirits refers to the one Holy Spirit. Some call Him the sevenfold Spirit.
Here are small sample.
“The seven spirits might conceivably refer to a group of angelic beings. But coming between references to the Father and the Son it is more probable that this is an unusual ways of designating the Holy Spirit.”
Canon Leon Morris, The Revelation of St. John
“He is called the seven spirits, not with regard to His essence, which is one, but with regard to His manifold operations.”
John Wesley, Notes on the Whole Bible
“The Spirit is one in name but seven-fold in virtues. Some think that (angels) are the seven Spirits mentioned here. But they cannot be; great as the angels were, they were still created beings.”
William Barclay, The Daily Study Bible Series
“The interpretation which would understand these seven Spirits to be the seven chief angels, though supported by names of great weight, is plainly untenable. The context makes it impossible to admit any other meaning than that the greeting which comes from the Father and the Son comes also from the Holy Spirit sevenfold in His operations, whose gifts are diffused among all the churches, and who divides to every man severally as He will.”
Ellicott’s Commentary for English Readers
“The Holy Spirit, sevenfold in his operations. They are before his throne, ever ready for a mission from him (comp. Revelation 7:15). The number seven once more symbolizes universality, plenitude, and perfection; that unity amidst variety which marks the work of the Spirit and the sphere of it, the Church.”
Where did this idea of the Holy Spirit being “the seven spirits” come from?
The reference appears to be from the prophet Isaiah
Isaiah 11:2 “Then a shoot will spring from the stem of Jesse, and a branch from his roots will bear fruit. The Spirit of the LORD will rest on Him, the spirit of wisdom and understanding, the spirit of counsel and strength, the spirit of knowledge and the fear of the LORD. And He will delight in the fear of the LORD, and He will not judge by what His eyes see, nor make a decision by what His ears hear…”
Seven expressions are in this text.
- Spirit of the LORD,
- Spirit of wisdom,
- Spirit of understanding,
- Spirit of counsel,
- Spirit of power,
- Spirit of knowledge,
- Spirit of the fear of the Lord.
All seven (or at least six) are functions or operations of the one Holy Spirit (mentioned in the first). These are “seven gifts of the Spirit with which Messiah is anointed, and the which animate and strengthen his body, the Church.”
As Moffat has written of Revelation 5:3,
“Elsewhere [Rev 4:5] the seven spirits are identified with seven torches, but John is more concerned to express from time to time his religious ideas than to preserve any homogeneity of symbolism”
As the seven lamps illumine, or give insight or knowledge of a thing, so too the Holy Spirit illumines, especially of sin, where his flaming presence purges the spirit and consumes evil (1 Cor 3:13; Heb 12:29), and also the baptism of fire (Mat 3:11). The seven stars are similarly inextricably linked to the lamps, the Messiah holding them firmly in his grasp (2:1), and holding them out (3:1) towards his church as the source of life and light. So again we have an image of the Holy Spirit.
What does the image “seven horns and seven eyes” mean?
Horns denote power in the Old Testament (see Deut 33:17; 1 Sam 2:1). Eyes denote knowledge (see Zec 3:9; 4:10; 2 Chr 16:9). The number seven denotes perfection. The symbol therefore attributed to the Lamb in Rev 5:6 denotes his complete power and wisdom, as per Matthew 28:18, “All power is given unto me in heaven and in earth.” It expresses God’s watchful providence and care.
It therefore means we can rely on the plans the Lamb of God has for us, for he oversees all things with the perfection of his knowledge and power.
 Pulpit Commentary, Zec 3:9
 Moffat, J. (n.d.). The Revelation of St. John the Divine. In The Expositor’s Greek Testament: Commentary (Vol. 5, pp. 384–385). New York: George H. Doran Company.