Weinandy on the Trinity

The Father begets the Son in or by the Holy Spirit.
The Son is begotten by the Father in the Spirit and thus the Spirit simultaneously proceeds from the Father as the one in whom the Son is begotten.
The Son, being begotten in the Spirit, simultaneously loves the Father in the same Spirit by which he himself is begotten (is Loved).

Thomas G. Weinandy, The Father’s Spirit of Sonship: Reconceiving the Trinity (Edinburgh: T & T Clark, 1995), 17.

Thus, all three Persons of the Trinity, within their relationships, help constitute one another.

My thanks to Myk Habets for drawing my attention to Weinandy's book.