The physics
Newton's third law: when A pushes B, B pushes A back.
The push back is just as hard. It points the opposite way. It acts at the same time.
F(A on B) = − F(B on A)
A pair always acts on two different bodies. It is always the same kind of force. Its two forces point opposite ways.
Two forces can balance on one body. That is Newton's first law, not a third-law pair.