8.
The Chapter on Strenuous Deeds
1-12.
The Twelve Discourses Beginning with Power
439-450. "Just as, monks, whatever activities requiring strength are done" - this should be expanded.
The Strenuous Deeds Chapter is the eighth.
Its summary:
Power and seed and elephant, tree with pot and sow;
With space and two clouds, boat, visitor, and river.