Victorinus of Pettau — on Rev 1:4 (Commentary on the Apocalypse of the Blessed John)

“"Grace unto you, and peace, from Him which is, and which was, and which is to come." He is, because He endures continually; He was, because with the Father He made all things, and has at this time taken a beginning from the Virgin; He is to come, because assuredly He will come to judgment. "And from the seven spirits which are before His throne." We read of a sevenfold spirit in Isaiah,1 -namely, the spirit of wisdom and of understanding, the spirit of counsel and might, of knowledge and of piety, and the spirit of the fear of the Lord.”