by Geerhardus Vos
a) It is God the Father by way of eminence. Since regeneration appears as something completely new, it fits with the economy of the Father that regeneration is ascribed to Him. “According to his great mercy, the God and Father of our Lord Jesus Christ has begotten us again to a living hope through the resurrection of Jesus Christ from the dead” (1 Pet 1:3; cf. also Jas 1:18; Eph 2:5; and the expression “born of God,” 1 John 5:1, 4, 18).
b) The Son is related to regeneration in more than one way.
1. He is the meriting cause. He has obtained the Holy Spirit, who works all subjective grace, and so has also obtained regeneration (Rom 5:18).
2. He is the head to whom believers are joined as members by regeneration, and who thus lives in them and expresses His life in them (Gal 2:20).
3. He is the image into which the believers are transformed in regeneration and to which continually they are also being increasingly conformed (1 Cor 15:49; Gal 4:19).
c) The Holy Spirit is the one who effects regeneration [John 6:63] for the sake of the Father and the Son in the heart of the sinner, as He in general organizes the mystical body of Christ.
From the chapter Regeneration and Calling in Vos, G. (2012–2016). Reformed Dogmatics. (A. Godbehere, R. van Ijken, D. van der Kraan, H. Boonstra, J. Pater, A. Janssen, … K. Batteau, Trans., R. B. Gaffin, Ed.) (Vol. 4, pp. 40–41). Bellingham, WA: Lexham Press.