Appearances of the Son
Just as in the days of the Old Testament, the Son of God in fact repeatedly appeared but did not choose human nature for his dwelling place until he was conceived in Mary’s womb, so also in earlier times various activities as well as the gift of the Holy Spirit were present.
Herman Bavinck, John Bolt, and John Vriend, Reformed Dogmatics: Sin and Salvation in Christ, vol. 3 (Grand Rapids, MI: Baker Academic, 2006), 501.