Ephesians 1:9 - Matthew Poole's English Annotations on the Holy Bible

Having made known unto us; having revealed to us outwardly by the preaching of the gospel; inwardly, by the illumination of the Spirit. The mystery of his will; the whole doctrine of grace and salvation by Christ, which is a secret to others, and had still been so to us, had not God discovered it to us in the gospel. According to his good pleasure; the good pleasure of God is the fountain of all spiritual blessings which flow out to us, as well as it is of our being first chosen and appointed to be the subjects of them. Which he hath purposed in himself; this signifies a firm, settled will in God, either merely of God, and moved by nothing out of himself, or his keeping this purpose in himself till the time appointed for the publication of it.