In looking for the context of this statement of Ireneus’s I discovered that it is actually used in the new Catholic catechism. I like it there so much I will copy and paste it below.
As I suspected, the statement “The glory of God is man fully alive,” taken out of context can be deceiving. It seems to imply that the way to glorify God is to just be yourself and follow your heart. Now, being yourself is very important — just look at what happens when you try to be someone else — but it’s important to remember that the only way to truly be yourself, a created being, is through and for the One who created you. The glory of God is man fully alive, but man fully alive is man glorifying God.
But I have better words waiting in my clipboard.
|ARTICLE NO. 293
Scripture and Tradition never cease to teach and celebrate this fundamental truth: “The world was made for the glory of God.” St. Bonaventure explains that God created all things “not to increase His glory, but to show it forth and to communicate it,” for God has no other reason for creating than His love and goodness: St. Thomas expresses it thusly. “Creatures came into existence when the key of love opened His hand.” The First Vatican Council explains:
This one, true God, of his own goodness and “almighty power,” not for increasing his own beatitude, nor for attaining his perfection, but in order to manifest this perfection through the benefits which he bestows on creatures, with absolute freedom of counsel “and from the beginning of time, made out of nothing both orders of creatures, the spiritual and the corporeal…”
ARTICLE NO. 294
The glory of God consists in the realization of this manifestation and communication of His goodness, for which the world was created. God made us “to be His sons through Jesus Christ, according to the purpose of His will, to the praise of His glorious grace,”(Eph. 1:5-6) for as St Irenaeus states; “the glory of God is man fully alive; moreover man’s life is the vision of god: if God’s revelation through creation has already obtained life for all the beings that dwell on earth, how much more will the Word’s manifestation of the Father obtain life for those who see God.” The ultimate purpose of creation is that God “who is the creator of all things may at last be all in all, thus simultaneously assuring His own glory and our beatitude.”(1 Cor.15: 28)