Source identified1
“whoever may Discern true ends here, shall grow pure enough To love them, brave enough to strive for them, And strong to reach them though the roads be rough”
The political poem links clearer ends with the character needed to pursue them, moving from discernment to courage, effort and persistence on a difficult road.
Source note: Casa Guidi Windows, Part II; Project Gutenberg #31015. Browning is writing specifically about Tuscan and Italian political freedom, so the excerpt is not detached from its Risorgimento context.