For every action there is an equal and opposite reaction.
Many have extrapolated this physical notion to diplomatic, military, and political affairs.
An object in motion tends to remain in motion along a straight line unless acted upon by an outside force.
To every action there is always opposed an equal reaction.
For every action there is an equal and opposite reaction. You never know what it’s going to look like on the other side, but you’ll see it eventually if you keep your eyes open.
Action and reaction are equal and opposite.
We are not to suppose, that there is any violent exertion of power, such as is required in order to produce a great event in little time; in nature, we find no deficiency in respect of time, nor any limitation with regard to power. But time is not made to flow in vain; nor does there ever appear the exertion of superfluous power, or the manifestation of design, not calculated in wisdom to effect some general end.
A system is in equilibrium when the forces constituting it are arranged in such a way as to compensate each other, like the two weights pulling at the arms of a pair of scales.
To every action there is always opposed an equal reaction, or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.