What does The Revolution Ends By Devouring Its Own Children mean?

The original revolutionaries, once they are mostly successful, are now worried about some future revolutionaries starting a different revolution, to redo the society once again. To the original revolutionaries, what they believed in was right. So, what's the need for another revolution, they think.

So, they do not want another revolution after their revolution, or a revolution within their revolution. In the chaos of their revolution, they have the incentive and means to wipe out anyone they think differs from their viewpoint. In the same chaos, someone else can wipe out the original revolutionaries, and hijack the revolution. The incentive of money, power, women, and future good life is far too much to resist.