I say móre: the just man justices; Keeps grace: thát keeps all his goings graces; Acts in God's eye what in God's eye he is — (9-11)
"Justices" is a weird verb here, but it's intentionally weird. The speaker's trying to show us that the best way to keep and represent God's grace (His favor) is to act strictly in accordance to our own inner character and sense of self. We have to match our actions to our innermost being. Significantly, we have to do so "in God's eye," to demonstrate our worthiness to Him.
Chríst — for Christ plays in ten thousand places, Lovely in limbs, and lovely in eyes not his To the Father through the features of men's faces. (12-14)
Christ is everywhere—potentially anywhere, at least. We have some tricky syntax here (surprise, surprise), but the upshot is that "Christ plays […] to the Father." In other words, Christ is performing His actions for the benefit of God. "Plays" is an odd choice of words, though. It this all fun and games to Christ?
Or maybe He sees Himself as a kind of actor. More likely, we might understand this as "Christ plays out in," or influences, lots of different settings and people. According to these lines, he seeks out folks who are acting according to their inner selves, blesses them with a visitation, and calls God's attention to them. Think of it as a divine seal of approval.