I've just finished reading Bavinck on 'Revelation in Nature and Holy Scripture' in Reformed Dogmatics: Volume One. The great Dutch theologian anticipates the language of Karl Barth, who famously suggested that 'God's being is in becoming.' Bavinck rightly relates the being and becoming of God to the enfleshment of Christ,
"The incarnation is the unity of being (ἐγὼ εἰμί, John 8:58), and becoming (σὰρξ ἐγένετο, John 1:14). - p. 380.