When a body is stationary
Consider a stationary block on a table. Gravity force (weight W=mg) acts downwards and normal reaction force from table acts upwards.
Hence, the combination of forces acting on it balance each other.
It is stated that every action has a equal and and opoosite direction so if a body is at rest and there there is no net externel force acting on it so there are any other force acting on the body like frictional is the force acts when only a body is in motion