Messages of the First Presidency 5:3; “But the Divine essence, called the Spirit of God, or Holy Spirit, or Holy Ghost by which God created or organized all things, and by which the prophets wrote and spoke, was bestowed in former ages and inspired the apostles in their ministry long before the days of Pentecost.”
Daniel 7:14; “And there was given him dominion, and glory, and a kingdom, that all people, nations, and languages, should serve him: his dominion is an everlasting dominion, which shall not pass away, and his kingdom that which shall not be destroyed.”
The Holy Spirit was given at Pentecost, not before. Yes, there were times God’s spirit came upon the prophets in the OT times but He did not reside inside of them.
Other scriptures to look at for this can be found in Jeremiah 31:31-34.