moral necessity
Puritan Board Junior
It is because we need grace (Unmerited Divine Influence) according to His riches
I am not aware of any reformed writers who refer to grace as "unmerited divine influence." I see where you're going with this, but, are you sure that you want to lose sight of grace still being "unmerited favor"? It's a fine tightrope we have to walk, and many, like myself, cringe when we hear phrases like this. It lead me back to the old scraping within myself and the absence of the joy and delight that unmerited favor brings. It alters the "guilt, grace, gratitude" formula, because grace now becomes influence instead of a motivator to good works.
I'll bow out for a while, as I know you're wanting your questions answered with Jack.
Blessings and fellowship!