Whether the armchair is empty or whether you are sitting in it doesn’t matter. It means that you are firmly established in your present position and no one can move you out of it without your permission.
Resting, being peaceful, as in Evening, Worship, and Prayer, but less religious in meaning. It may, however, also be a sign of laziness or boredom, and point to the fact that you act like a ruler.
Take time to relax every now and then.