For the meaning of Eminent - expansion. Harvest - determination click HERE
"Serve" see here
Line 2. or: 'A flood - grasp your chance! It will end regret'.
Line 4. One's group is flooded... There are hills in the flood. No foreign tribes, a place to think. Lynn: in a time of dispersion, there is a mountain of unsettled thoughts.
Line 5. 'Floods of perspiration' is also an imperial edict "as perspiration once produced cannot be recalled, so an edict cannot be revoked" (Mathews' 2252).
Line 6. blood: sorrow or family ties.