If you’ve not heard the cast recording from Hamilton, you’re missing out – it’s memorable from first to last.
Although I’m not big on standalone quotes, here’s one, from that musical’s Washington on Your Side, that’s both memorable and, I think, often figuratively true:
If there’s a fire you’re trying to douse,
You can’t put it out from inside the house
(It’s not a direct historical quote from anyone, to my knowledge, but rather clever lyrics. Jefferson and Madison sing these words in the musical.)
There’s much to be said for an independent position, for a policy of distance, detachment, and (in all cases) diligence.