To stand Moses: a man is said to stand Moses when he has another man’s bastard child fathered upon him, and he is obliged by the parish to maintain it.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Mort * MossNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes