“[God] destined us for adoption as His children through Jesus Christ, according to the good pleasure of His will, to the praise of His glorious grace that He freely bestowed on us in the Beloved” (Eph. 1:5-6).
Because I have already commented on the content of v. 5, I will focus here on what Paul says in v. 6, though I have quoted both verses so as to show the complete thought.
Paul has finished telling us about our predestination, how God has chosen us in Christ before the foundation of the world to be holy and blameless before Him in love, to which end He has provided for us every spiritual blessing in Christ in the holy places, all the while adopting us into His family through our union with Christ, the only-begotten Son of God, and all this not because of any merit on our part, but simply because it pleased Him to do so — such is His loving and gracious character. Then, in v. 6, Paul tells us one of the consequences of God’s glorious act of election, begun in eternity and realized in history through Jesus Christ: all this is “to the praise of His glorious grace.”
When we contemplate God’s mercy and love towards us, how He chose us and wanted us as His children even before the world began, how He guided all things in history towards the revelation of His mercy for all His creatures in Jesus Christ, the natural result is that we praise Him. Indeed, what could constitute a better reason to praise and to love God than the fact that He is forever and immutably “for us,” on our side, disposed towards us in love, willing to do everything necessary to save us from our sins and to bring us into His family, to share His life with us, and in short to grant us beatitude in His Kingdom? If a person believes this even a little bit, the very thought is enough to warm the heart and to bring to full blossom a bud of praise which has been planted in the soul.
I think it is good to make a habit of thinking of these things, reminding ourselves of God’s tremendous love for us. And of course, as Paul emphasizes once more, for the fourth time in as many verses, this love has a face — the face of Jesus Christ, who is God Incarnate, the perfect “exegesis” of the Father for us (cf. John 1:18), who shows us that God is love and that He loves us, as T.F. Torrance so memorably said, even more than He loves Himself, because He is willing to give His life for us.