A toast, which is a must when drinking, symbolises friendship, community and love, and an important ritual of building trust. This ritual originates from kings, whilst feasting, clashing their goblets together to mix the drinks, thus proving that they did not poison each other’s drink.
Ergo, the ritual that symbolises “trust” originates from the meaning of “I will not kill you”.
As an addendum, Ancient Romans used to also add pieces of burnt bread into glasses of wine because people were led to believe that charcoal reduced acidity in wines. Hence the origination of the term “toast”. The act of toasting, however, came from ancient Greece.