What is the origin of the idiom "hand in hand" and when to use it?

The idiom "go hand in hand" is derived from the physical act of two people walking or moving together while holding each other's hands. This literal practice of walking hand in hand signifies unity, cooperation, and mutual support. The idiom extends this idea to describe situations where two elements or factors are closely connected and work together in a harmonious or complementary manner, often reinforcing each other's influence. Its origin lies in the universal gesture of physical connection and cooperation.