What does Machiavelli mean when he talks about ability?

Answer 1

The primary ability that concerns Machiavelli is ability of mind - cunning and foresight. Physical prowess is of much less concern since, as a ruler, you can probably get many other people to perform a physical task for you, if need be. But exactly who you should trust, when, and for what tasks are decisions that a 'prince' can only make for himself, or else be a puppet of the person who DOES make those decisions.

Further evidence of this lies in the examples he cites - not just soldiers and generals, but also religious and social leaders of all stripes, many of whom quite obviously had no personal experience with war whatsoever (though the cited 'successful' ones were almost always called on to wage it, according to Machiavelli).

Hope that helps!