We are so much accustomed to talk about the influence of the Holy Ghost and his sacred operations and graces, that we are apt to forget that the Holy Spirit is truly and actually a person–that he is a subsistence–an existence; or, as we Trinitarians usually say, one person in the essence of the Godhead. I am afraid that, though we do not know it, we have acquired the habit of regarding the Holy Ghost as an emanation flowing from the Father and the Son, but not as being actually a person himself. I know it is not easy to carry about in our mind the idea of the Holy Spirit as a person. I can think of the Father as a person, because his acts are such as I can understand. I see him hang the world in ether; I behold him swaddling a new-born sea in bands of darkness; I know it is he who formed the drops of hail, who leadeth forth the stars by their hosts, and calleth them by their name; I can conceive of Him as a person, because I behold his operations. I can realize Jesus, the Son of Man, as a real person, because he is bone of my bone and flesh of my flesh. It takes no great stretch of my imagination to picture the babe in Bethlehem, or to behold the “Man of sorrows and acquainted with grief,” of the king of martyrs, as he was persecuted in Pilate’s hall, or nailed to the accursed tree for our sins. Nor do I find it difficult at times to realize the person of my Jesus sitting on his throne in heaven; or girt with clouds and wearing the diadem of all creation, calling the earth to judgment, and summoning us to hear our final sentence. But when I come to deal with the Holy Ghost, his operations are so mysterious, his doings are so secret, his acts are so removed from everything that is of sense, and of the body, that I cannot so easily get the idea of his being a person; but a person he is. God the Holy Ghost is not an influence, an emanation, a stream of something flowing from the Father; but he is as much an actual person as either God the Son, or God the Father.
Spurgeon’s Sermons (Spokane, Washington; Olive Tree Bible Software; 2010) eBook. Vol. 1, Sermon No. 4; Titled: The Personality of the Holy Spirit; Delivered on Sabbath Morning, January 21, 1855.