I agree with most of what Big J said, another great episode. A lot went on to really beef up the character profiles. Nucky's juggling seemed clearly meant to symbolically represent his character, constantly juggling everything around him. Margaret's song was also representative of her character. She sings "The Belle of Belfast." Just the first verse which goes:
Tell my ma when I go home,
The boys won't leave the girls alone,
They pulled my hair and stole my comb,
But that's all right 'till I go home.
She is handsome, she is pretty
She is the belle of Belfast city,
She is courting, one two three
Please won't you tell me who is she?
I think it's basically a metaphor for her situation (the three she's courting) being married to Nucky, smashing Owen and wanting the Doctor.
And does no one want to talk about the obvious motif of saying grace? Nucky/Eli and the fam, Gyp and his fam, Harrow and the soldiers, Harrow by himself, Jillian and Bizarro Jimmy. This episode definitely had a ton of religious overtone, aside from just Gyp's masterful monologue. I'd have to watch it again to see what they were implying but I think they mostly just wanted to ground this episode with some spirituality.
Most underrated line of the episode was "show some leg"