The Eucharist (also called Holy Communion or the Lord's Supper, among other names) is a Christian rite that is considered a sacrament in most churches and an ordinance in others. According to the New Testament, the rite was instituted by Jesus Christ during his Last Supper; giving his disciples bread and wine during the Passover meal, Jesus commanded his followers to "do this in memory of me" while referring to the bread as "my body" and the wine as "my blood". Through the Eucharistic celebration Christians remember Christ's sacrifice of himself on the cross. 

The elements of the Eucharist, bread (leavened or unleavened) and wine are consecrated on an altar (or table) and consumed thereafter. Communicants (that is, those who consume the elements) may speak of "receiving the Eucharist", as well as "celebrating the Eucharist". Christians generally recognize a special presence of Christ in this rite, though they differ about exactly how, where, and when Christ is present. While all agree that there is no perceptible change in the elements, Catholics believe that they actually become the body and blood of Christ (transubstantiation). Lutherans believe the true body and blood of Christ are really present "in, with, and under" the forms of the bread and wine (sacramental union). Reformed Christians believe in a real spiritual presence of Christ in the Eucharist. Others, such as the Plymouth Brethren, take the act to be only a symbolic reenactment of the Last Supper.
Did he order them to take it?
Jesus commanded his followers to