If you're a figurative painter with a desire to produce a narrative painting, then obviously you're going to need to consider what your figures will be doing in your painting. A key consideration is selecting a gesture and a posture to convey whatever information you're trying to get across. These considerations are broadly thought of as "body language", which are particularly important in the case of a "traditional" painting where you wouldn't have text or any particular verbal clue as to what the artist intends (unless you have a fairly obvious title for your painting, perhaps).
Eisner starts first by discussing gestures. These drawings below are very broad, theatrical gestures, caricatured for comic purposes, of course. You might want to tone gestures down in a painting, or even make a gesture as neutral as possible, but you'll understand what he means here:
Will Eisner, Comics and Sequential Art, p. 104 (my scan)
You're going to have to put your figure in some kind of posture, too. Broadly speaking, a posture is an visually recognizable attitude or position manifested by a figure, such as resting or digging a hole with a shovel. Your figures can be in an infinite variety of postures and you'll have to select one which best expresses your plan for your artwork. Your selected pose is then "frozen in time" on your canvas, so you'll want to select a position which most accurately describes the action or situation you want to convey:
Will Eisner, Comics and Sequential Art, p. 107 (my scan)
How do you feel about each of these figures in the two rectangles above? Which one looks more aggressive to you, the one with the arm reaching toward you, or the one with the shield up? They're the same figure, of course, but do you see how simply selecting a different pose changes the focus of our attitude toward the figure? It's the same figure, but (and this is important, I think) at different points in time.
Remember also that even a figure at complete rest, with a sleeping, neutral expression, is in a posture, and it's a living posture, not the attitude of a dead body (see yesterday's blogpost).
Making artwork come alive, with movement and, a little later in history, sound, is of course the province of the animated film. More on this later on.