Both the republic and state granted lands for military service in the form of bounty and donation grants.
"By an act of 1879 certificates for an additional 640 acres were granted under stringent restrictions to indigent veterans of the Texas Revolution. Bounty and donation grants for military service amounted to a total of 3,149,234 acres."
Basically, as a reward or an incentive for their service in multiple battles.
The revolution in Haiti took place when a large portion of the islands slave population rose against their colonial masters. Many Americans were concerned that the revolt would inspire slaves in the US to do the same thing.