Henceforth thou art the genius of the shore, In thy large recompense. And shalt be good To all that wander in that perilous flood (183-185)
Now Lycidas is the friend of all sea-faring people. That's his "recompense" or reward for suffering a terrible death before his time. An entire new community is established – between Lycidas and "all that wander in that perilous flood." This community will outlive both Lycidas and the poem's speaker. Hey, the more friends the better, right?