Question

Can anyone help explain what these quotes mean?

"A pure democracy can admit no cure for the mischiefs of faction. A common passion or interest will be felt by a majority, and there is nothing to check the inducements to sacrifice the weaker party. Hence it is, that democracies have ever been found incompatible with personal security or the rights of property; and have, in general, been as short in their lives as they have been violent in their deaths."

“All men of sense will agree in the necessity of an energetic executive … The ingredients which constitute energy in the executive are u

Answer 1

This means it's simply the observation that in a pure democracy - in which the majority can make or unmake any law with no limitation - the majority will be able to mistreat the minority. So, for example, the ancient Athenians voted to exile Socrates for holding and teaching unpopular opinions.
I hope my answer helped you