"... a Lamb standing, as though it had been slain, having seven horns, and seven eyes, which are the seven Spirits of God, sent out into all the earth"
This verse as well as 3:1 and 4:5 speaks about "seven spirits of God".
This is commonly interpreted as "seven" to mean numerological completeness or perfectness rather than literal seven, because (accordingly this interpretation) "spirit of God" refers to an entity which exists singularly. I seek alternate interpretations of this.
I interpret this as "seven angels (or other spiritual entities) belonging to God, who serve as Christ's eyes to look after the Earth", but this conflicts with understanding "the spirit of God" to denote the Holy Spirit (understood by Christians as the third person of God). However, in the New Testament this is usually phrased as the "Holy Spirit" not "Spirit of God".
Can we establish (from both linguistic, historical and theological views) that in the New Testament "Holy Spirit" and "Spirit of God" are (or are not) synonyms?
In considering this, is the phrase "Spirit of God" ever used in the New Testament instead of "Holy Spirit" (excluding the above mentioned verses)?