Supposing that the intent is to contrast the "seven spirits" of Revelation with the singular "spirit" mentioned elsewhere, here is a little from the BECNT-Revelation (Grant R. Osborne, p.61):
The second source, "the seven spirits that are before his [God's] throne," is also debated. While many think the Πνευμάτων (pneumaton, spirits) are angels (see additional notes for details), it is better to see this in light of Isa. 11:2 LXX (which adds a seventh virtue, "godliness," to the six in the MT) and Zech 4:2, 10 (with seven lamps as "the eyes of the LORD, which range throughout the earth") as referring to the "sevenfold Holy Spirit," with seven emphasizing the Spirit's perfect work (so also De Smidt 1994: 241). The key is Zech. 4:6, where the "LORD Almighty" defines this action as "not by might, nor by power, but by my Spirit." As Baukham (1993a: 110-11) brings out, the Spirit then is the means by which God will destroy the might and power of the dragon and the beast. Three other texts mention "the seven spirits": in Rev 3:1 Christ "holds the seven spirits of God," showing that he is the Spirit of Christ; in 4:5 seven lamps are blazing before the throne of God, and in 5:6 the "sevenfold Spirit" is characterized even more closely with Zechariah, as the Lamb is described as having "seven eyes, which are the seven spirits of God sent out into all the earth, building on the "seven lamps . . . sent out" in Zech 4:2. The sevenfold Spirit is both "of God" (3:1; 4:5) and of the Lamb (5:6). Swete (1911: 6) believes that the sevenfold nature of the Spirit here is also due to the fact that he ministers to the seven churches of Asia, where the Spirit is the basis of the message and the key to their understanding and obedience ("hear what the Spirit says to the churches").
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