Twice He is styled the Spirit of grace, since He is the dispenser of the divine favor to all men, either by conviction of sin in order to bless them by turning them away from their iniquities, or by imparting to believers spiritual life, witnessing to their adoption and perfecting their holiness.
He is called also the Spirit of supplication because He teaches us how to pray and for what to pray; the Spirit of revelation because He reveals Christ to the eye of faith; the Spirit of wisdom because He imparts wisdom; the Spirit of adoption because He certifies the believer's sonship; and the Spirit of Christ because He was sent by the Father through the mediation of the Son. He is called the Spirit of God because He is one with God in His nature. This leads us to the scriptural proofs that the Holy Spirit is consubstantial with God and is a person. The two doctrines of the personality and the divinity of the Spirit go together. The identity of God and the Spirit of God runs through the Holy Scriptures. Whoever the Spirit is, there is no distinction between Him and God, just as there is no distinction between the man and the spirit of the man (I Cor. ii. 11).
— The Gospel of the Comforter (1898) Chapter 1.