Ephesians 1:11 In whom also we were designated as an inheritance... (12) That we would be to the praise of His glory who have first hoped in Christ
The little word “that” at the beginning of verse 12 is very meaningful. It indicates that the many things that have been taking place in the preceding verses have a certain result: that we should be to the praise of God's glory. This verse does not mean that we shall praise God.
It means that so much will be worked out for us and in us by God's abounding grace that all the angels and positive things in the universe will praise God. They will praise God because we, the sons of God, will be the center, the focal point, of God's operation in the universe. We on whom, for whom, and in whom the abounding grace is accomplishing so much will become the cause for the praise uttered by the positive things in the universe.
Praise is the utterance of appreciation. We do not praise clay because we do not appreciate it. The day is coming when we, the sons of God, will be appreciated by all the angels.
The more they look at us, the more utterance they will have that will flow out as praise to God. Their appreciation of us will become their praise to God. They will realize that what we are is the work of God's abounding grace.
The amount of praise depends upon how much work the abounding grace has done.