In this post I will quoting from St. Augustine’s On the Holy Trinity, Book 15. All emphasis will be mine.
Chapter 25.— The Question Why the Holy Spirit is Not Begotten, and How He Proceeds from the Father AND the Son, Will Only Be Understood When We are in Bliss.
For if any belong to Him, although far duller in intellect than those, yet when they are freed from the body at the end of this life,…