There is no ancient gentlemen but gardeners, ditchers, and grave-makers: they hold up Adam's profession.
Act V, Scene 1
Context
The First Clown argues that gravediggers are the most ancient profession, tracing their lineage back to Adam, the first man, who worked the earth.
Analysis
By invoking 'Adam's profession,' the gravedigger collapses the distance between biblical origin and present labor, claiming a dignity for manual work that the word 'gentleman' usually denies. The list—'gardeners, ditchers, and grave-makers'—links those who plant life with those who bury death, all united by their handling of earth. The phrase 'hold up' is doing double work: these professions uphold (continue) Adam's work and also hold up (support) the pretensions of 'ancient gentlemen' by literally digging their graves.
Essay Tip
Support a thesis that Shakespeare uses the gravedigger scene to invert social hierarchies—by claiming Adam as the first laborer, the Clown makes all inherited nobility look like a recent invention compared to the ancient dignity of those who work the ground.