Jesus is continuously being sacrificed every time a Mass occurs. The Lutheran doctrine is similar to the Catholic view. Jesus death occurs again when the bread and wine enter the person. Jesus died only once to pay for our sins. This is not found in the scripture.
Communion is a spiritual event.
The word is not in the scriptures. Used by a number of churches. Decided by each local church, but it should not become merely ritualistic without meaning. This could occur if it is a daily or weekly part of the service. As part of a love feast and during a Passover seder.