God’s perfection means that God completely possesses all excellent qualities and lacks no part of any qualities that would be desirable for him.

This attribute is as much a part of all the others as it’s one on it’s own. The subject of a “perfect” God comes up (Ps. 18:30, cf. Deut. 32:4) as does our own pursuit of it as Jesus recommends (Matt. 5:48). There is no quality of excellence that would be desirable for God to possess: he is “complete” or “perfect” in every way.

God’s blessedness means that God delights fully in himself and in all that reflects his character.

To be “blessed” is to be and feel satisfied. Old books express this feeling as “sanguine” or “felicity.” The definition reflects the fact that God is satisfied with his creation and how it reflects on himself (cp. Gen. 1:31). We, ourselves “are blessed” to be here at all in that we have nothing to do with it (cp. 1 Cor. 4:7, Ja. 1:17), nothing at all. This reality, most are completely numb to it, at our best reflects God’s character in what we say and how we live.

When we reflect God’s blessedness in those things pleasing to God, both from our own actions and those of others, we imitate our Lord’s satisfaction in the blessedness of creation. It reveals the many aspects of his most excellent character.