The Holy Spirit's Deity in the Old Testament

Isaiah says Israel rebelled against and grieved God's Holy Spirit. Psalm 78 says Israel rebelled against and grieved God himself.
The two passages use the same pair of Hebrew verbs - marah, to rebel, and atsab, to grieve - in the same context. The only thing that changes is the object. In one it is the Spirit. In the other it is God.
That is the argument, and it is a strong one. It identifies the Spirit with the God of Israel.
A note on how much weight to place on it. The sources describe these Old Testament passages as whispers of the idea of a Godhead rather than a finished doctrine. This is where the groundwork is laid, not where the matter is settled.
Scripture links:
- Isaiah 63:10-11 - they rebelled and grieved his Holy Spirit.
- Psalm 78:40-41 - they rebelled against him and grieved him.
Two passages, one pair of verbs, and a conclusion the later church spent centuries learning to put into words.