But the Helper will teach you everything and cause you to remember all that I told you. This Helper is the Holy Spirit that the Father will send in my name.
(Gospel of John chapter 1 verse 14, ERV)
Basil of Caesarea was one of the most important theologians the Christian Movement has ever had. Both Catholics and Orthodox consider him a "Doctor (in the sense of a great teacher) of the Church." Here Basil blogs one his many demonstrations that the Holy Spirit is God.
The Father, the Son and the Holy Spirit all make holy, revive, enlighten, and comfort. No one would attribute a special, peculiar duty of making holy to the the Spirit after hearing the Savior ask the Father this about his disciples in the Gospel: "sanctify them in Your name, (Gospel of John chapter 17 verse 17, CEB). In the same way all other tasks are performed equally, for all those worthy of them, by the Father, by the Son, and by the Holy Spirit -- every grace and virtue, guidance, life, comfort, transformation into immortality, the passage into freedom and every other good thing that comes down to humanity... The Father, Son, and Holy Spirit performing one and the same duties clearly proves that they are of the same nature. It follows then that, even if the name of "Godhead" does signify God's nature, their common essence proves that this title is also quite properly applied to the Holy Spirit.
Basil of Caesarea, also known as Saint Basil the Great (AD 329 - 379)
Letter 189 chapter 7